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OLIVEE EVANS, 

THE WATT OF AMERICA. 



A CATECHISM 

OF 

HIGH PRESSURE 

OR 

Non-Condensing Steam Engines. 

INCLUDING THE 

MODELING, CONSTRUCTING, RUNNING AND 
MANAGEMENT 

OF 

STEAM ENGINES AND STEAM BOILERS. 
affiith Illustrations, 



By STEPHEN ROPER, 

ENGINEER. 



PHILADELPHIA:^ 
CLAXTOX, EEMSEN & HAFFELFINGER, 
624, 626 & 628 Market Street. 
18 74. 



t; 



Entered, according to Act of Congress, in the year 1873, by 

STEPHEN ROPER, 

in the Office of the Librarian of Congress, at Washington. 



~^A J - FAGAN & S0N » felS^L. 

^^ &L* STEREOTYPERS, PHILAD'A. *J^*^ 



Selheimer k Moore, Printers, 
501 Chestnut Street. 



"& 6 - ^ 



11 



THIS VOLUME 
is 



Mwafed 



TO 



ARTHUR ORE, J). M. P., 

AS A TRIBUTE OF RESPECT TO HIS EMINENT ABILITIES 
AS AN ENGINEER AND MECHANIC. 



INTRODUCTION. 



THE writer of the following pages has made it his 
study to produce a work for the use of practical en- 
gineers, by furnishing them with a simple and clear ex- 
planation of each subject treated. In its preparation a 
great effort has been made to secure accuracy, and to 
render every subject plain and easy of comprehension, 
by treating it in a clear style, taking up each subject in 
regular order and examining it by the light of daily 
experience. The range of subjects comprehends every- 
thing directly connected with the steam-engine and 
steam-boiler. At the end of many of the articles, tables 
have been appended and examples introduced, to make 
explicit and distinct the principles set forth. 

Many of the books heretofore published have been 
written by men of mere theory, for the purpose of in- 
structing practical engineers in matters which the authors 
have never learned. Abstract theory can never meet the 
wants of practical men, nor instruct them in the discharge 
of their duties. But the writer does not wish to be con- 
sidered an unbeliever in theories ; because theories can 
never be dispensed with by any class of men, however 
unlearned, as theories aid us in the discovery of new facts 
and new truths. A book, however, to be useful to all classes 



Ylll INTRODUCTION". 

of engineers, must give strong evidence of the author's 
experience as a practical engineer. The writer has had 
an experience of over thirty years with every description 
of engines and boilers, and in the preparation of this 
little book he has drawn almost entirely upon his own 
experience and observation. His aim has been to convey 
his meaning, to those for whom it is intended, by means 
of plain language, with familiar and practical illustra- 
tions, and to instruct those who are intrusted with the 
care and management of steam-engines and steam-boilers, 
so that they may understand with certainty whether they 
are deriving the greatest amount of practical advantage 
from the power they have generated. Hints and exam- 
ples have also been given, intended to show how a great 
many practical improvements can be made by engineers 
and owners of steam-engines. 

Another feature of the work, and one which it is be- 
lieved will greatly benefit engineers of limited education, 
is that the use of decimals has been dispensed with, and 
fractions also, except those expressed by the common 
signs, J, }, |, &c. 

In order to render the book useful to those who employ 
or are employed about steam-engines, the writer has en- 
deavored to embody all the necessary information rela- 
tive to improvements in the construction, use and man- 
agement of steam-engines and steam-boilers that have 

come into use up to the present time. 

S.E. 



CONTENTS. 



fk PAGE 

Introduction vii 

The Steam-Engine 13 

Water . 15 

Table showing the Weight of Water in Pipes of 

Various Diameters One Foot in Length . 19 

Air 20 

Table of Expansion of Air by Heat. Showing 
the Increase of Bulk in Proportion to the 
Increase of Temperature ... . .22 

Heat 23 

Table showing the Temperature required to 
Ignite different Substances . . . .27 

The Thermometer 27 

Comparative Scale of English, French and Ger- 
man Thermometers %*' 29 

Steam , ' 30 

Table showing the Temperature of Steam at 

different Pressures 35 

The Engineer 36 

The Steam-Boiler 41 

Cylinder Boilers 44 

Flue Boilers 46 

Tubular Boilers . . . . . 47 

Double-Deck Boilers 49 

Locomotive Boilers 49 

Mud-Drums . 50 

Boiler-Heads 51 

Boiler-Shells .... . b2 
Table deduced from Experiments on Iron Plates 
for Steam-Boilers, by the Franklin Institute, 

Philadelphia .59 

Table deduced from Experiments on Iron of dif- 
ferent Boilers, by the Stevens Institute of 

Technology .60 

Steel Boilers 61 

ix 



CONTENTS. 



PAGE 

62 

. 64 

67, 68, 69, 70 

. 71 



Internal and External Pressures 

Eules 

Table of Internal Pressures . 

Foaming in Steam-Boilers 

Rust 

Patent Steam-Boilers 

The Safety- Valve 

Rules 

Table for Safety- Valves 

Feed- Water Heaters . . . . 
Fuel 

Table showing the Total Heat of Combustion of 
Various Fuels . . . . 

Chimneys . 

Smoke . . . . 

Grate-Bars 

Duties of an Engineer in the Care and Man- 
agement of the Steam-Boiler . 
Steam- Engines 

Table showing the Average Pressure of the 
Steam upon the Piston throughout the Stroke 116 

Lap on the Slide- Valve 118 

Table showing the Amount of " Lap " required 
for Slide- Valves when the Steam is to be 
worked expansively- 
Lead on the Slide- Valve 

''Cushion" 

Setting Valves 

Size of Steam-Port 

Size of Steam-Pipe . 

Size of Exhaust-Pipe 

Size of Piston-Bod . 

Material for Different Parts of Engines 

Spring- Packing 

Proportions of Engines 

Reversing an Engine 

Putting an Engine in Line 

Setting up Engines 

Table containing the Circumferences and Areas 
of Circles from 4 to 26 inches in Diameter 134-137 



72 
72 
73 
76 
79 
80 
83 

85 

85 
87 
89 

93 
106 



120 
121 
123 
124 
126 
127 
127 
127 
128 
129 
129 
130 
130 
132 



CONTENTS. 



EULES FOR THE CARE AND MANAGEMENT OF 

the Steam-Engine 

Different Kinds of Engines 
Knocking in Engines .... 

Vacuum 

The Indicator 

Explanation 

Tip marks • •••••* 

Eule for Computing the Power of a Diagram 
The Governor . . . . • •„ ' 

Short Rules for Calculating the Size of Pulleys 

for Governors 

The Injector 

Table of Capacities of Injectors . 

Steam-Pumps 

Centrifugal Pumps . . . . • 
Noiseless Boiler Feed-Pump .... 
Directions for Setting Up Steam-Pumps . 
Table containing the Diameters, Circumferences, 
and Areas of Circles, and the Cubical Con- 
tents of Cylinders, in Gallons 
Piston-Rod Packing .... 

Incrustation 

Boiler Explosions .... 
Steam- and Fire-Regulator 
Central and Mechanical Forces 

Mensuration 

Circle, Cylinder, Sphere, etc . 

Belting 

Leather Belts 

Lacing Belts .... 
Horizontal Belts .... 
Perpendicular Belts .... 
Greasing Belts 
Rules for Finding the Proper Width of Belts 
Rules to be Observed in case of Accidents 
A Brief History of the Steam-Engine . 

History of the Different Parts of the Steam 

Engine in Detail 

Vocabulary 



138 
142 
149 
151 
154 
164 
165 
165 
166 

170 
170 
174 

176 

178 

180 
180 



182 
184 
185 
193 
198 
200 
201 
201 
205 
206 
207 
207 
207 
208 
208 
209 
210 



212 
213 




THE ENGINEER'S CHART. 



A CATECHISM 

OF 

HIGH PKESSURE, 

OR 

NON-CONDENSING STEAM-ENGINES. 



THE STEAM-ENGINE. 

IN the early records of the human race, whenever 
power was required in order to provide for hu- 
man wants, it was supplied by the muscles of human 
beings, or by those of horses, oxen, or other animals. 

But men soon learned to supplement muscular 
power with that created by the descent of water, and 
by the winds of heaven. In modern times even 
these sources of power have been to a great extent 
superseded by steam, and at the present day there 
is hardly any purpose for which power is required, 
that is not furnished by the steam-engine. 

Of all the efforts of human ingenuity known, per- 
haps none has monopolized so large a share of inven- 
tive genius as the steam-engine. No other object in 
the entire range of human devices has so irresistibly 
arrogated to itself the devotion of scientific men, as 
2 13 



14 CATECHISM OF HIGH PRESSURE, OR 

the production of an artificial movement from the 
vapor of boiling water. 

The progressive history of the invention com- 
mences with the days of Hero of Alexandria, two 
thousand years ago, and advances down through the 
labors of the Marquis of Worcester, of Savery and 
Papin, to the days of Watt, whose splendid improve- 
ments of the working principle of the steam-engine 
are well known. 

In late years the improvement of the steam-engine 
has been steady, rather than remarkable in any one 
particular. It has advanced by improvement in 
construction, rather than by the development of any 
new principle. The facilities for the manufacture of 
steam-engines, and the amount of capital invested in 
that branch of mechanics, has increased very rapidly 
within the last few years. 

Thousands of skilled workmen are continually in- 
venting ingenious devices to replace the different 
parts of the engine now in use, and modifications are 
constantly resorted to to secure good construction 
and general improvement. 

As might be expected, we find an infinite variety 
of constructions, some of inferior design, inferior 
workmanship, and inferior finish, whilst others have 
splendid symmetrical proportions, elaborate finish, 
and beautiful and simple mechanism. 

But still there appears to be a wide field open for 
experiment and improvement in the steam-engine, 



NON-CONDENSING STEAM-ENGINES. 15 

since it is asserted by persons competent to judge, 
that first-class engines yield less than ten per cent, of 
the work stored up in good fuel, and the average en- 
gines probably utilize less than four per cent, of the 
fuel. 

The best steam-engine, apart from its boiler, has 
about five-sixths of the efficiency of a perfect engine. 
The remaining sixth is lost through waste of heat by 
radiation and conduction externally, and by conden- 
sation and friction externally. It is to improve- 
ments in these points that inventors must turn their 
attention. 

WATER. 

Q. What are the constituent parts of fresh-water? 

A. Oxygen and hydrogen. 

Q. In what proportion ? 

A. Oxygen, 89 parts by weight, and by measure 1 
part ; hydrogen, by weight 11 parts, and by measure 
2 parts. 

Q. How many cubic feet of fresh-water make 1 
ton? 

A. 36 cubic feet. 

Q. How many cubic feet of sea-water make 1 ton ? 

A. 35 cubic feet. 

Q. How do you account for the difference in 
weight between sea- and fresh-water?. 

A. Sea-water is more dense. 



16 CATECHISM OF HIGH PRESSURE, OR 

Q. How much does a cubic foot of water weigh ? 

A. 62J pounds. 

Q. How many gallons in a cubic foot of water ? 

A. 6 J- gallons. 

Q. How much does a cubic inch of water weigh ? 

A. About i an ounce. 

Q. How much does a cylindrical foot of water 
weigh ? 

A. 49 pounds. 

Q. What is the weight of a cylindrical inch of 
water ? 

A. Nearly i an ounce. 

Q. How much does a cubic foot of ice weigh ? 

A. 68J pounds. 

Q. What is the boiling-point for water ? 

A. 212° Fah. 

Q. What is the freezing-point of water ? 

A. 32° Fahrenheit. 

Q. What is the difference between water, ice, and 
steam ? 

A. Water is a fluid, ice is a solid, steam is a vapor. 

Q. What is the difference in volume between 
water and steam at the pressure of the atmosphere ? 

A. 1700 ; that is to say, that any given quantity 
of water will make 1700 times that amount of steam 
at a pressure of 15 pounds to the square inch, or at- 
mospheric pressure. 

Q. At what temperature does water attain its 
greatest density ? 



NON-CONDENSING STEAM-ENGINES. 17 

A. 39° Fah. 

Q. Is water compressible ? 

A. No : it presses in every direction and finds its 
level. 

Q. "What is the centre of pressure of a column of 
water ? 

A. § of its depth from the surface. 

Q, At what degree of temperature does the water 
boil in a vacuum ? 

A. 98° Fah, 

Q. At what degree of temperature does water be- 
come solid ? 

A. 32° in the open air. 

Q. Does water expand in freezing ? 

A. Yes. 

Q. Do all fluids expand with heat ? 

A. Yes ; all fluids expand with heat, and contract 
with cold down to 40° Fah. 

Q. Are all waters equal for the production of 
steam ? 

J.. No ; sea-water, or other waters holding salt in 
solution, require a higher temperature to produce 
steam of the same elastic force. 

Q. How is the gravity of water ascertained ? 

A. By means of a hydrometer. 

Q. If water be boiled in an open vessel, can the 
temperature of the water be raised above 212° Fah.? 

A. No ; as all the surplus heat which may be ap- 
plied passes off with the steam. 
2* B 



18 CATECHISM OF HIGH PRESSURE, OR 

Q. How do you explain the theory of ebullition, 
or boiling water ? 

A. In this way ; that in metals heat is communi- 
cated by the conducting properties they possess, but 
in liquids heat is communicated by a separation of 
particles. 

Q. If heat be applied to the top of a vessel con- 
taining water, will ebullition take place ? 

' A. No *, as very little heat will be communicated to 
other parts of the vessel, and the water will never boil. 

Q. Is it a common thing in steam-boilers to indi- 
cate a larger supply of water than that which really 
exists in the boiler ? 

A. Yes ; as the steam is forming in the water it 
rises in bubbles to the surface, which by their bulk 
displace a great amount of water, indicating a great 
rise at the gauge-cocks. 

Q. What is the vaporization of water ? 

A. It is the conversion of water, as a liquid, into 
vapor as steam. 

Q. What is solidification ? 

A. It is a change which water undergoes from a 
liquid to ice as a solid. 

Q. Does the density of water increase with its 
depth? 

A. Yes ; there is a theoretical depth at which water 
would become as dense as iron. 



NON- CONDENSING STEAM-ENGINES. 



19 



TABLE 

Showing the Weight of Water in Pipes of Various 
Diameters One Foot in Length. 



Diameter 


Weight 


Diameter 


Weight 


Diameter 


Weight 


in Inches. 


in Pounds. 


in Inches. 


in Pounds. 


in Inches. 


in Pounds. 


3 


3 


12} 


51 


23 


180} 


31 


3* 


12* 


53} 


23* 


188} 


3J 


4} 


12f 


55* 


24 


196} 


3| 


4f 


13 


57* 


24* 


204* 


4 


54 


m 


59f 


25 


213 


41 


6} 


13* 


62} 


25* 


221* 


41 


7 


13| 


64* 


26 


230* 


4| 


7| 


14 


66| 


26* 


239* 


5 


8^ 


14} 


69} 


27 


248* 


5i 


9} 


14} 


71* 


27* 


257f 


51 


10i 


14| 


74} 


28 


267} 


5| 


Hi 


15 


76| 


28* 


276| 


6 


m 


15J 


79J 


29 


286* 


61 


13} 


15} 


82 


29* 


296* 


6} 


14* 


15f 


84* 


30 


306| 


61 


15i 


16 


87} 


30* 


317} 


7 


16| 


m 


90 


31 


327* 


71 


18 


16* 


92} 


31* 


338} 


n 


20| 


16| 


95* 


32 


349 


7| * 


17 


98* 


32* 


360 


8 


21f 


m 


101* 


33 


371} 


81 


23} 


m 


104* 


33* 


382* 


81 


24* 


17| 


107* 


34 


394 


81 


26 


18 


no* 


34* 


405| 


9 


27* 


18} 


113* 


35 


417* 


91 


29} 


18* 


116* 


35* 


429* 


91 


30| 


18|- 


119| 


36 


441 J 


91 


32* 


19 


123 


36* 


454 


10 


34 


19i 


126| 


37 


466* 


101 


35| 


19* 


129* 


37* 


479} 


101 


37* 


19| 


132 


38 


492} 


101 


39} 


20 


136} 


38* 


505} 


11 


41* 


20* 


143} 


39 


518* 


111 


43i 


21 


150} 


39* 


531| 


111 


45 


21* 


157* 


40 


545* 


111 


47 


22 


165 






12 


49 


22£ 


172* 







20 CATECHISM OF HIGH PRESSURE, OR 

AIR. 

Q. What are the constituent parts of air, or what 
does air consist of? 

A. It consists, by volume, of oxygen 21 parts, of 
nitrogen 79 parts, and by weight, of oxygen 77 parts, 
and of nitrogen 23 parts. 

Q. Does any other gas enter into the constituent 
parts of air ? 

A. Yes ; in 1,000,000 parts of air there are 4 parts 
of carbonic acid. 

Q. How many cubic feet in 1 pound of air ? 

A. 13,817 cubic feet. 

Q. What is the weight of 1 cubic foot of air at 
the surface of the earth, temperature 34° Fah.? 

A. 527 grains, or J ounce avoirdupois. 

Q. What is the difference in weight between air 
and water ? • 

A. Air is 829 times lighter than water. 

Q. What is the mean weight of a column of air 1 
inch square and 45 miles high ? 

A. 15 pounds, 

Q. Is the pressure of the air the same at all alti- 
tudes? 

A. No ; at 7 miles above the surface of the earth 
the air is 4 times lighter than at the earth's surface ; 
at 14 miles, 16 times ; at 21 miles, 64 times. 

Q. How much air does it require to consume 1 
pound of coal ? 



NON-CONDENSING STEAM-ENGINES. 21 

A. 18 pounds, or 240 cubic feet. 

Q. Is it possible to construct an air-engine of any- 
great power ? 

A. No; as air, like all other gases, expands but 
one volume for each 493° of temperature through 
which it is raised ; and in order to double its volume, 
we must raise it 493° more, which will bring it to a 
temperature of 986° Fah., which is entirely too 
high for practical purposes. Even if air could be 
worked at this temperature, it would be necessary to 
have a feed-pump of nearly the capacity of the en- 
gine, which w T ould be very cumbrous, and the engine 
itself w r ould have to be more than twice the size of a 
steam-engine of the same power. 

Q. Is it possible to obtain much power from air at 
a lower temperature ? 

A. Yes ; but as w T e lower the temperature, we must 
increase the capacity of the engine and pump, which 
will become very bulky and expensive. 

Q. Is the expansion of air, like all other elastic 
fluids, uniform at all temperatures ? 

A. Yes ; the following table will show the rate of 
expansion of and according to temperature : 



22 



CATECHISM OF HIGH PRESSURE, OR 



TABLE. 

Expansion of Air by Heat. Showing the Increase of 
Bulk in Proportion to the Increase of Temperature, 



Fahrenheit. 


Bulk. 


Fahrenheit. 


Bulk. 


Temp 


. 32 Freezing-poinl 


. 1000 


Temp. 75 


. 1099 


ti 


33 


. 1002 




76 Summer heat. 


.1101 


ft 


34 


. 1004 


tt 


77 


. 1104 


It 


35 


. 1007 


tt 


78 


. 1106 


tt 


36 


. 1009 


tt 


79 


. 1108 


tt 


37- 


. 1012 


n 


80 


. 1110 


tt 


38 


. 1015 


n 


81 


. 1112 


it 


39 


. 1018 


it 


82 


. 1114 


it 


40 


1021 
. 1023 
. 1025 
. 1027 


tt 
ti 
tt 
it 


83 

84 

85 

86 


. 1116 


tt 


41 


. 1118 


tt 


42 


. 1121 


tt 


43 


. 1123 


tt 


44 


. 1030 


tt 


87 


. 1125 


it 


45 


. 1032 
. 1034 

. 1038 


it 
it 
tt 
it 


88 

89 .... 

90 • 

91 ..<.•:... 


. 1128 


it 


46 


. 1130 


tt 


47 


. 1132 


tt 


48 


. 1134 


tt 


49 




ti 


92 


. 1136 


tt 


50 


. 1043 


n 


93 , 


. 1138 


tt 


51 




n 


94 


. 1140 


it 


52 


. 1047 


it 
tt 


95 

96 Blood heat 


. 1142 


it 


53 


. 1144 


it 


54 


. 1052 


tt 


97 


. 1146 


tl 


55 




it 


98 


. 1148 


tt 


56 Temperate 


1057 


it 


99 


. 1150 


tt 


57 




ti 


100 


. 1152 


tt 


58 


1062 


it 


110 Fever heat 112 1173 


tt 


59 


1066 


ti 
ti 


120 

130 


. 1194 


tl 


60 


. 1215 


tt 


61 




tt 


140 


. 1235 


tt 


62 


1071 


tt 


150 


. 1255 


tt 


63 




ti 


160 


. 1275 


tt 


64 


1075 


tt 


170 Spirits boil 176 1295 


it 


65 


1077 
1080 


tt 
tt 


180 

190 


. 1315 


a 


66 


. 1334 


n 


67 




tt 


200 


. 1364 


tt 


68 


1084 


ti 
tt 


210 

212 Water boils.... 


. 1372 


tt 


69 


. 1375 


it 


70 


1089 


ti 


302 


. 1558 


it 


71 




it 


392 


. 1739 


it 


72 


1093 


tt 


482 


. 1919 


tt 


73 




it 


572 


. 2098 


a 


74 


1097 


it 


680 


. 2312 



SON-CONDENSING STEAM-ENGINES. 23 

HEAT. 

Q. What is heat? 

A. It is a species of motion, or one form of me- 
chanical power. 

Q. Is heat capable of producing power ? 

A, Yes ; and power is capable of producing heat. 

Q. With any given degrees of temperature, and 
any given expenditure of heat, will the amount of 
power generated be the same ? 

A. Yes. 

Q, What is specific heat ? 

A. Specific heat of a substance is an expression for 
the quantity of heat in any given weight of it at cer- 
tain temperatures. 

Q. What is sensible heat ? 

A. That which is sensible to the touch. 

Q. What is latent heat ? 

A. It is that which a body absorbs in changing 
from a solid to a fluid state. 

Q. What is meant by the radiation of heat ? 

A. It is the effect produced by the direct rays of a 
hot body through space. 

Q. Is the latent heat in steam uniform at all tem- 
peratures ? 

A. No ; neither is the total amount of heat the 
same at all temperatures. 

Q. Does the total and latent heat in steam increase 
with the pressure ? 



24 CATECHISM OF HIGH PRESSURE, OR 

A. No; as the sensible heat increases the latent 
heat diminishes. 

Q. Can the absolute heat of any body be deter- 
mined? 

A. Only by the relative heat of other bodies at the 
same temperature. 

Q. What is combustion ? 

A. It is an energetic combination of gases, or a 
mutual neutralization of opposing electricities. 

Q. Does the quantity of heat in any body vary 
with the temperature ? 

A. Yes; the temperature of steam rises with the 
pressure. 

Q. What method is adopted to determine temper- 
atures so high that no thermometer can give a relia- 
ble result? 

A. We take a body, such as platinum, and place 
a mass of this metal in a blast furnace, and when the 
mass has acquired the temperature of the furnace we 
transfer it to a vessel containing a known weight of 
water. We can then observe the rise of temperature 
by means of an ordinary thermometer. 

Q. How do you determine the specific heat of dif- 
ferent bodies ? 

A. By mixing different substances together at dif- 
ferent temperatures, and noting the temperature of 
the mixture. For instance, when water is at 100° and 
mercury at 40°, the mixture will be at 80° ; the 20° 
lost by the water causes a rise of 40° in the mercury. 



NON-CONDENSING STEAM-ENGINES. 25 

Q. What is a unit of heat ? 

A. The unit of heat is the amount of heat required 
to raise the temperature of 1 pound of water 1°, or 
from 32° to 33° Fah. 

Q. What is the mechanical equivalent of heat? 

A. The power necessary to raise 1 pound 772 feet 
high. 

Q. What is the capacity of any body for heat ? 

A. It is the relative power of a body in receiving 
and retaining heat at any given temperature. 

Q. What is the reflection of heat ? 

A. It is the passage of heat from one surface to 
another, or into space. 

Q. What is the communication of heat ? 

A. It is the passage of heat to different bodies with 
different degrees of velocity. 

Q. What is the transmission of heat ? 

A. It is the passage of heat through different 
degrees of intensity. 

Q. How much heat does a pound of water receive 
in passing from a liquid at 212° Fah. to a vapor at 
212°? 

A. It receives as much heat as would raise it 966° 
if the heat was sensible as well as latent. 

Q, What is conversion of heat ? 

A. It is the transfer or diffusion of heat in a fluid 
mass by means of its particles. 

Q. Will water boil in a vacuum with less heat 
than under the pressure of the atmosphere ? 
3 



26 CATECHISM OF HIGH PRESSURE, OR 

A. Yes ; in a vacuum water boils at 98° to 100°, 
according as the vacuum is perfect. 

Q. Does water give out heat in freezing ? 

A. Yes ; water in freezing gives 140° of heat. 

Q. At what degree of temperature do fluids evapo- 
rate in a vacuum ? 

A. From 100° to 120° below the boiling-point. 

Q. What is a thermal unit ? 

A. It is the quantity of heat required to raise 1 
pound of water 1°, the water being at its maximum 
density (= 39° Fah.). 

Q. How can the amount of heat stored up in any 
fluid, that might be utilized by perfect mechanism, 
be shown ? 

A. It must be represented by a fraction, the nu- 
merator of which is the temperature of the fluid 
while doing its work, and the denominator the tem- 
perature of the fluid when entering a vessel, to be 
measured from absolute zero. 

Q. Does the nature of the medium upon which 
heat acts in the production of power make any 
difference ? 

A. No ; whether water, air, metal, or any other 
substance is the medium, it is immaterial, except so 
far as the agent is convenient and manageable ; and 
just in the proportion in which power is generated, 
»o will heat disappear. 



NON-CONDENSING STEAM-ENGINES. 



27 



TABLE. 

The following Table will show the Temperature required 
to Ignite different Substances. 

Name of Substance. Temp, of Ignition. 

Phosphorus 140° Fah. 

Bisulphide of Carbon 300° 

Fulminating Powder 374° 

Fulminate of Mercury 392° 

Gun-Cotton . 428° 

Nitro-Glycerine 494° 

Eifle-Powder 550° 

Forced Gunpowder 563° 

Picrate Powder for Torpedoes 570° 

Charcoal from Willow Wood 660° 

Picrate Powder for Cannon 715° 

Very Dry Pine Wood 800° 

Dry Oak Wood 900° 

Steam, 100 lbs. per square inch pressure.. 332° 
Steam, 200 " " " " " 387° 

Steam, 240 " " " " " 403° 



THE THERMOMETER. 

Q. What is an absolute zero ? 

A. It is the point at which heat-motion is supposed 
to cease entirely, estimated to be 461° Fah. below 
the zero of the common scale. 

Q. How is the zero of the common scale fixed ? 

A. It is fixed by mixing salt with snow until the 
mercury in the tube falls 32° below the freezing- 
point for water. 

Q. What do you mean by Fahrenheit ? 

A. I mean Fahrenheit's scale or thermometer, the 
one generally used in this country. 

Q. What do you mean by Centigrade ? 



28 CATECHISM OF HIGH PRESSURE, OR 

A. I mean the Centigrade scale or thermometer, 
by which they measure temperatures in France. 

Q. What do you mean by Reaumur ? 

A. I mean Reaumur's rule or thermometer that is 
commonly used in Germany. 

Q. What is the difference between Fahrenheit's, 
Centigrade, and Reaumur's rules ? 

A. Fahrenheit's zero is 32° below freezing, boiling- 
point of water 212° ; Centigrade, zero 32° or freezing, 
boiling-point 100° ; Reaumur's, zero 32° or freezing, 
boiling-point 80°. Hence Fahrenheit 180°, Centi- 
grade 100°, Reaumur 80°. 

Q. What are fixed temperatures ? 

A. One the melting-point of ice, and the other 
the boiling-point of pure water. 

Q. Why do you call these fixed temperatures ? 

A. Because it is impossible to raise the tempera- 
ture of ice above 32° Fah., and no amount of heat 
will raise boiling water above a temperature of 212° 
Fah., if contained in an open vessel. 

Q. Does the thermometer indicate the amount of 
heat in any body ? 

A. No ; only the changes in temperature. 

Q. What is a differential thermometer ? 

A. An instrument that measures minute differ- 
ences of temperature. 



NON-CONDENSING STEAM-ENGINES. 



29 



COMPARATIVE SCALE OF ENGLISH, FRENCH 
AND GERMAN THERMOMETERS. 



Boiling-point 100 - 
of water. 

90 - 

80 - 


j 


212 


£ 


- 80 Boiling-point 

of water. 

- 70 


— 


200 
190 

180 


— 




170 


- 60 


70 - 




160 


— 




150 




60 - 
50 - 


— 


140 

130 
120 
110 


- 50 

- 40 


40 - 


100 




- 30 

- 20 

- 10 

_ Freezing-point 

- 10 

- 20 


30 - 
20 - 
10 - 
Freezing-point.. - 
10 - 
20 - 
30 - 


90 
80 
70 
60 
50 
40 
30 


— 


— 


20 

10 

ZERO 

10 
20 
30 




— 


40 


- 30 


Mercury freezes 40 - 










— 


- 40 



3* 



30 CATECHISM OF HIGH PRESSURE, OR 

STEAM. 

Q. What is steam ? 

A. Steam is vapor arising from water at a temper- 
ature of 212° Fah. 

Q. What are the most prominent properties pos- 
sessed by steam? 

A. First, its high expansive force ; second, its prop- 
erty of condensation ; third, its concealed or unde- 
veloped heat. 

Q. By whom were the expansive properties of 
steam discovered ? 

A. By Hornblower, who obtained a patent for his 
invention in 1781. 

Q. From what cause does the expansive force of 
steam arise ? 

A. From the absence of cohesion between the par- 
ticles of water. 

Q. How is the condensation of steam effected ? 

A. By the abstraction of its temperature. 

Q. What is the difference in volume between 
water and steam at a temperature of 212° Fah.? 

A. 1700 ; that is to say, any given quantity of 
water converted into steam at the pressure of the at- 
mosphere or 212° Fah., will present a volume 1700 
times greater than its original bulk. 

Q. Can steam mix with air? 

A. Not while its pressure exceeds that of the at- 
mosphere. 



N0N- CONDENSING STEAM-ENGINES. 31 

Q. If a cylinder be filled with steam at a pressure 
of 15 pounds to the square inch, will the air be 
expelled from the cylinder ? 

A. Yes. 

Q. Now as the existence of the steam depends upon 
its temperature, by abstracting that temperature will 
the steam assume the state due to its reduced tem- 
perature? 

A. Yes ; by immersing the cylinder in cold water 
the steam contained therein is condensed into water. 

Q. Now, as the water cannot occupy the volume 
which it did under its former temperature, what is 
the result? 

A As the steam in the cylinder is condensed by 
the abstraction of its heat, the result will be a va- 
cuum. 

Q. What is the amount of latent or concealed 
heat that exists in steam ? 

A. The latent heat of steam, though showing no 
effect on the thermometer, may be easily shown by 
placing 5J pounds of water in a vessel at 32° Fah., 
and admitting steam through a pipe from another 
vessel until the temperature of the water in the first 
vessel is raised to the boiling-point. It will then be 
discovered that the weight of the water in the vessel 
is 6 J pounds. 

Q. How do you account for this additional pound 
of water ? 

A. It is the result of the admission of one pound 



32 CATECHISM OF HIGH PRESSURE, OR 

of steam to the vessel ; and this pound of steam, while 
retaining its own temperature of 212°, has raised 5J 
pounds of water 180°, or an equivalent to 990°, and 
including its own temperature we have 1202°, which 
the pound of steam must have possessed at first. 

Q. Is the sum of latent and sensible heat of steam 
nearly constant? 

A. Yes ; and does not vary much from 1200°. 

Q. If a known volume of steam of a certain press- 
ure be made to occupy J that volume, is its elastic 
force doubled ? 

-4. Yes ; the same pressure is exerted within } of 
its original capacity. 

Q. What do you mean by steam pressure ? 

A. I mean the initial elastic force of the steam, 
which is always the same in equal weights of steam. 

Q. Does the elasticity of steam increase with an 
increase of temperature ? 

A. Yes, but not in the same ratio ; because if 
steam is generated from water at a temperature which 
gives it the pressure of the atmosphere, an additional 
temperature of 38° will give it a temperature of two 
atmospheres, and a still further addition of 42° will 
give it a pressure of 4 atmospheres. 

Q. Why is it that every additional degree of tem- 
perature between 40 and 50 doubles the pressure ? 

A. The heat in generating the steam has to over- 
come the attraction among the particles of water, and 
likewise of the gravity of the water itself; and as the 



NON-CONDENSING STEAM-ENGINES. 33 

water becomes rarefied by heat, the attraction and 
gravity become diminished, and an additional tem- 
perature does not have to contend with the same re- 
sistance as the one that preceded it. 

Q. Is steam in itself invisible ? 

A. Yes ; and it only becomes visible by loss of 
temperature, as when a jet is discharged into the 
open air, and is then seen in the form of vapor. 

Q. In treating of steam, why are the terms heat 
and caloric used ? 

A t The term heat is understood as expressing sen- 
sible heat, while the term caloric expresses every 
conceivable existence of temperature. 

Q. Is steam produced from impure water equal in 
density to steam from pure water? 

A. No ; steam from pure water, at a temperature 
of 212° Fah., supports a column of mercury of 30 
inches, while steam from sea or impure water, at the 
same temperature, supports only 22 inches. 

Q. Can the heat of steam be raised to a very high 
temperature ? 

A. Yes ; steam can be heated to nearly a red heat, 
but not while it is held in contact with water. 

Q. Does the temperature of steam at ordinary 
pressure contain heat enough to ignite wood ? 

A. Not without the intervention of some other 
substance, such as linseed oil, greasy rags, or iron 
turnings. 

Q. How do you explain that ? 
C 



34 CATECHISM OF HIGH PRESSURE, OR 

A. Because we know that the temperature of 
superheated steam is only about 400° Fah., and it 
requires more than double that intensity of heat to 
ignite wood. See Table under the head of Heat 

Q. What is liquefaction ? 

A. It is the condensing of steam through the 
abstraction of heat. 

Q. Do you know of any reliable rule for connect- 
ing the temperature and elastic force of saturated 
steam ? 

A. No ; various formulas have been at different 
times introduced for the purpose of deducing the 
elastic force of saturated steam, but without any very 
reliable or satisfactory results. 

Q. Can you tell the number of superficial feet of 
steam-pipe necessary to warm any room or number 
of rooms? 

A. One superficial foot of steam-pipe to 6 superfi- 
cial feet of glass in the windows, or 1 superficial foot 
of steam-pipe for every 100 square feet of wall, roof 
or ceiling, or 1 square foot of steam-pipe to 80 cubic 
feet of space ; 1 cubic foot of boiler is required for 
every 1500 cubic feet of space to be warmed. One 
horse-power boiler is sufficient for 40,000 cubic feet 
of space. 



NON-CONDENSING STEAM-ENGINES. 



35 



TABLE. 

Showing the Temperature of Steam at different Pressures, 
from 15 pounds per Square Inch to 100 pounds, and the quan- 
tity of Steam produced from a Cubic Inch of Water according 
to Pressure. 



Total 






Total 






Pressure 


Corresponding 


Cubic Inches of 


Pressure 


Corresponding 


Cubic Inches 


of- Steam 


Temperature of 


Steam from a 


of Steam 


Temperature of 


of Steam from 


in lbs. 


Steam to 


Cubic Inch of 


in lbs. 


Steam to 


a Cubic Inch of 


perSquare 


Pressure. 


Water accord- 


perSquare 


Pressure. 


Water accord- 


Inch. 




ing toPressure. 


Inch. 




ing toPressure. 


15 


212.8 


1669 


58 


292.9 


484 


16 


216.3 


1573 


59 


294.2 


477 


17 


219.6 


1488 


60 


295.6 


470 


18 


222.7 


1411 


61 


296.9 


463 


19 


225.6 


1343 


62 


298.1 


456 


20 


228.5 


1281 


63 


299.2 


449 


21 


231.2 


1225 


64 


300.3 


443 


22 


233.8 


1174 


65 


301.3 


437 


23 


236.3 


1127 


66 


302.4 


431 


24 


238.7 


1084 


67 


303.4 


425 


25 


241.0 


1044 


68 


304.4 


419 


26 


243.3 


1007 


69 


305.4 


414 


27 


215.5 


973 


70 


306.4 


408 


28 


247.6 


941 


71 


307.4 


403 


29 


249.6 


911 


72 


308.4 


398 


30 


251.6 


883 


73 


309.3 


393 


31 


253.6 


857 


74 


310.3 


388 


32 


255.5 


833 


75 


311.2 


383 


33 


257.3 


810 


76 


312.2 


379 


34 


259.1 


788 


77 


313.1 


374 


35 


260.9 


767 


78 


314.0 


370 


36 


262.6 


748 


79 


314.9 


366 


37 


264.3 


729 


80 


315.8 


362 


38 


265.9 


712 


81 


316.7 


358 


39 


267.5 


695 


82 


317.6 


354 


40 


269.1 


679 


83 


318.4 


450 


41 


270.6 


664 


84 


319.3 


346 


42 


272.1 


649 


85 


320.1 


342 


43 


273.6 


635 


86 


321.0 


339 


44 


275.0 


622 


87 


321.8 


335 


45 


276.4 


610 


88 


322.6 


332 


46 


277.8 


598 


89 


323.5 


328 


47 


279.2 


586 


90 


324.3 


325 


48 


280.5 


575 


91 


325.1 


322 


49 


281.9 


564 


92 


325.9 


319 


50 


283.2 


554 


93 


326.7 


316 


5t 


284.4 


544 


94 


327.5 


313 


52 


285.7 , 


534 


95 


328.2 


310 


53 


286.9 


525 


96 


329.0 


307 


54 


288.1 


516 


97 


329.8 


304 


55 


289.3 


508 


98 


330.5 


301 


56 


290.5 


500 


99 


331.3 


298 


57 


291.7 


492 


100 


332.0 


295 



36 CATECHISM OF HIGH PRESSURE, OR 

THE ENGINEER. 

The duties of an engineer intrusted with the care 
and management of a steam-engine and steam-boilers, 
are of more importance than would appear at first 
sight, as the mechanics of any other class might be 
ignorant or neglectful of duty without subjecting 
themselves or their employers to any danger or much 
inconvenience ; but ignorance or neglect of duty on 
the part of an engineer, might at any time result in 
great destruction to life and property. 

Steam-boilers require constant care and attention, 
1 and when in charge of careful and intelligent engi- 
neers are perfectly safe, when well-constructed ; but 
when their management falls into the hands of reck- 
less and ignorant men, they become a source of con- 
stant danger to their owners and the public. For 
the above reasons any engineer who may offer to take 
charge of an engine and boiler ought to be able to 
show that he fully understands the duties and responsi- 
bilities involved in their care and management. He 
ought to be able to calculate safety-valve lever ex- 
amples, and thoroughly understand the principles in- 
volved. He should also be able to calculate the 
pressure required to burst a boiler when all the di- 
mensions are given. He should understand the dif- 
ference between longitudinal and curvilinear strains, 
the difference in value between single- and double- 
riveted seams, and the comparative strength of the 



NON-CONDENSING STEAM-ENGINES. 37 

shell, flues, and other parts of the boiler. He should 
also fully understand the causes which tend to produce 
explosions, and be conversant with all the details of 
construction, use and management of steam-boilers. 
But, above all, he should be a man of good sound 
sense and intelligence. 

Now, it requires time, study and experience to ac- 
quire the above fund of information ; and if the engi- 
neer should qualify himself accordingly, will his in- 
telligence be appreciated and his services be remu- 
nerated by steam users? Yes; undoubtedly they 
will, as there seems to be a steady and increasing de- 
mand for skilled workmen in this country in every 
branch of mechanics — and in none more so than in 
steam - engineering. Perhaps there may be some 
steam users who do not desire the services of a good 
engineer, for the reason that they think he might in- 
terpose an intelligent remonstrance against their 
recklessness in the use and management of their 
steam-boilers, or he might decline to gratify their 
avarice by allowing himself to be degraded to the 
position of man-of-all-work. Not being familiar with 
the properties of steam themselves, many owners of 
steam-boilers seem to think that almost any man — 
no matter how ignorant he may be — can in a short 
time qualify himself for the position of an engineer ; 
it not seeming to occur to them that there is no place 
where experience and intelligence are of so much im- 
4 



38 CATECHISM OF HIGH PRESSURE, OR 

portance as they are in the care and management of 
steam-boilers. 

It is also a frequent assertion of some steam users 
that a great many engineers are incapable. They 
seem to forget that the same thing might be said of the 
members of any other trade or profession. But it might 
be said, without fear of contradiction, that engineers in 
general are as capable and intelligent as any other 
class of mechanics. Even if the above assertion is 
true — that a great many engineers are incapable — 
it might be pertinent to the question to ask : Are • 
they wholly to blame? or does some of the responsi- 
bility rest with the owners of steam-engines and 
steam-boilers, w T ho have been for years encouraging 
ignorance and incapacity by employing incompetent 
men, from motives of false economy ? 

Under such circumstances, it is not to be wondered 
at that a great many errors have found their way 
into the business ; but the remedy for nearly all of 
them is within reach of the engineers themselves — 
more particularly the young men. They must edu- 
cate themselves, so that their opinion on all questions 
connected with steam - engineering will give strong 
evidence that they fully understand the principles 
and practice of their profession, then their opinions 
will command respect, and their services be corre- 
spondingly remunerated. They must remember that 
it is not the trade that elevates the man, but it is 
rather the man that dignifies the pursuit or calling ; 



NON-CONDENSING STEAM-ENGINES. 39 

and that muscular power, though very good in its 
place, is not the most essential requisite of an engi- 
neer, but that the cultivation of the mind is the first 
step towards eminence in any trade or profession. 

It is true that in steam-engineering, as in all other 
trades, there are a great many men who are totally 
unfit for the business — men that, perhaps, would 
succeed, to a certain extent, in some other pursuit, 
but who become a failure, and often a reproach to 
the profession they have adopted, simply for the rea- 
son that they have made a mistake in the selection 
of a suitable trade. 

Although no modern writer on steam or the steam- 
engine has made any allusion to engineers, or called 
public attention to the importance of their education 
to steam users and the public, still it cannot be 
denied that engineers have made very creditable 
progress in the acquirement of knowledge connected 
with their business within the past ten years. But 
yet there seems to be ample room for improvement 
on the part of both engineers and their employers, 
and that such change will soon come there is no 
reason to doubt. For improvement in steam-engines 
and steam-boilers will also require more able manage- 
ment ; and intelligent steam users will begin to see 
that the most important essentials to the economical 
working of the steam-boiler and steam-engine are 
care, skill and intelligence, and these qualifications 
will liberally repay all the money expended in se- 
curing them. 



40 CATECHISM OF HIGH PRESSURE, OR 




PLAIN CYLINDER BOILER. 




PLUE BOILER. 




TUBULAR BOILER. 



NON-CONDENSING STEAM-ENGINES. 41 

THE STEAM-BOILER. 

In the choice of steam-boilers, the three most im- 
portant objects to be attained are safety, durability, 
and economy. 

To secure safety, it is necessary that the boiler 
should be made of good material, with good work- 
manship. 

To secure durability, the boiler ought to be con- 
structed so as to give the greatest facilities and 
easiest access for cleaning, repairing, and renewal of 
any of its parts. The boiler should also be so de- 
signed as to avoid unequal strains by expansion and 
contraction as far as possible. 

In attempting to secure economy in the generation 
of steam, it is necessary, first, to secure perfect com- 
bustion of the fuel, so as to produce the greatest 
amount of heat; second, to apply the heat in the 
very best manner to the boiler, so as to heat the 
water in the most rapid manner possible ; third, great 
care must also be taken to prevent the heat escaping 
by radiation, or with the products of combustion. If 
these three conditions be complied with, our arrange- 
ments will be of the most economical character. The 
evaporative efficiency of any boiler and furnace is to 
be measured by the amount of water evaporated by 
any given weight of fuel in a given time. Mere 
waste of fuel, however, is not the only defect attend- 
ant upon an inferior construction of boiler and fur- 
4* 



42 CATECHISM OF HIGH PRESSURE, OR 

nace. Where these are not of the best kind, they 
must be of larger size in order to do the required 
amount of work ; the grate-surface must be larger, and 
more air must be needlessly raised to a higher tem- 
perature, thus carrying off a large amount of heat in 
the waste products of combustion ; all of which in- 
volves increased outlay of capital and larger running 
expenses. 

Many of the defects of modern boilers might be 
attributed, first, to the fact that some of the inventors 
or designers seem to be partly, if not totally, igno- 
rant of the first principles of mechanical science ; 
second, to competition between boiler-makers them- 
selves, in their efforts to undersell each other, conse- 
quently they have to deceive purchasers and steam 
users by magnifying small boilers into large ones. 
Therefore, when the boiler comes to be tested, its 
evaporative powers are found to be lacking, the fuel 
has to be burned under a sharp draught, and instead 
of the best results, the worst are obtained. 

In regard to the metal of the boiler itself, it is a 
well known fact that the thicker the iron is, and the 
poorer its conducting qualities, the greater will be 
the amount of heat that will be lost or wasted ; when 
by using a superior quality of iron, one whose tensile 
strength and conducting powers are both very great, 
we lessen the resistance to the passage of the heat 
from the furnace to the water and greatly increase 
the economy of the boiler. It is well known to en- 



NON-CONDENSING STEAM-ENGINES. 43 

gineers that some qualities of iron are two and a half 
times stronger than others ; consequently, if we make 
a boiler of poorer iron than would be as strong as I 
inch of the best iron, we should have to use plates f 
of an inch thick. Even then a heavy boiler would 
be w T eaker than the light one, from the fact that the 
heavy plates would sustain great injury in the 
making. In point of economy and durability, the 
light boiler would be far superior to the heavy one. 

Every attempt to lessen the first cost of a boiler 
by diminishing the heating- and grate-surface is, to a 
certain extent, carrying out the principle of " penny 
wise and pound foolish." 

An engine extra large for the work to be done 
causes a loss of fuel, whilst a boiler extra large for 
the work to be done makes a great saving. 

A boiler taxed to its full evaporative capacity will 
evaporate from 5 to 6 pounds of water to 1 pound of 
coal. Double the size of the boiler, and you will get 
the same amount of steam with 35 to 40 per cent, 
less fuel. 

The quantity of water evaporated depends not only 
on the heating-surface, grate-surface, and draught, 
but also on the quantity of air which passes through 
the furnace in a given time. 

For instance: a locomotive boiler burning 10 
pounds of coal on each square foot of grate-surface in 
an hour, will evaporate about 8 pounds of water for 
each pound of coal. The same boiler, running at a 



44 CATECHISM OF HIGH PEESSUKE, OR 

high speed; and burning 75 pounds of coal on each 
square foot of grate-surface, will evaporate 7 pounds 
of water for each pound of coal burned. Here is a 
vast difference in the total amount of evaporation, — 
each pound of coal produces less steam in the pro- 
portion of 9 to 7 pounds. 

So that it will be seen that the economy of fuel 
in one case is very evident ; in the other, it will be 
seen that the waste of fuel under a forced draught is 
very great. 

A boiler may generate steam with great economy, 
but, owing to the steam being wasted by improper 
application to the engine, the result is unsatisfactory, 
and the boiler unjustly blamed. A boiler that car- 
ries out water with its steam may show a large evapo- 
ration, but the steam being wet, is almost useless in 
the engine. 

The maximum evaporative capacity of any boiler 
is the amount of water it would evaporate in 10 hours 
from a temperature of 60° Fah., with good fuel, good 
draught, and the steam allowed to escape as fast as 
generated. 

Steam-boilers are of almost every kind and de- 
scription : cylinder, tubular, and flue ; upright, hori- 
zontal, inclined, and patent. 

CYLINDER EOILEES. 

Q. What advantage do cylinder boilers possess 
over other boilers ? 



N0X-C0XDEXSING STEAM-EXGIXES. 45 

A, First, the old plain cylinder boiler is light, is 
easy to clean and repair ; second, it is less dangerous, 
and requires less attention than any other kind of 
boilers now in use. 

Q. What are the disadvantages of the cylinder 
boiler, or why is it so fast passing out of use, more 
particularly in cities ? 

A. First, the cylinder boiler, on account of its ex- 
treme length, is un suited to cities, where space is so 
limited and of great value ; second, because it re- 
quires a greater amount of fuel to evaporate a certain 
amount of water than any other boiler now in use ; 
third, because it takes so long to raise steam from 
cold water. 

Q. What do you believe to be the most economical 
length for a cylinder boiler ? 

A, It is found by experience that the length of a 
cylinder boiler should never exceed 7 times its diam- 
eter. 

Q. What might be considered a horse-power in a 
cylinder boiler ? 

A. The term horse-power, as applied to the steam- 
boiler, has no definite application. It has been cus- 
tomary to fix on some unit of heating- and grate-sur- 
face as the unit of horse-power for a boiler ; and that 
unit is about 15 square feet of heating-surface, and 
I of a square foot of grate-surface to the horse-power 
in cylinder boilers. 

Q. What would you call a fair evaporation of 
water in a cylinder boiler ? 



46 CATECHISM OF HIGH PRESSURE, OR 

A. 6 pounds of water to one pound of coal. 

Q. How should cylinder boilers be set ? 

A. Cylinder boilers, or any other boiler, should 
have an incline of 1 inch to every 20 feet towards 
the end where the blow-off is situated. In case cylin- 
der boilers are extremely long, they ought to be sup- 
ported in the centre with a midfeather. 

FLUE BOILEES. 

Q. What are the advantages and disadvantages 
of flue boilers ? 

A. The advantage is that they occupy less room 
than the cylinder, from the fact that they present a 
greater amount of heating-surface. The disadvan- 
tages are, 'first, they are heavier than the cylinder ; 
second, they cost more ; third, they are difficult to 
repair or clean ; fourth, they are very dangerous on 
account of the liability of the flues to collapse. 

Q. In making flue boilers, what proportion should 
be carried out in regard to the flues ? 

A. They should always be made of small diam- 
eter, not more in any case than 12 or 14 inches, for 
the reason that small diameters give them greater 
strength. 

Q. In case it should be necessary to make flues of 
large diameter, say 18 or 20 inches, what is the best 
plan of constructing them ? 

A. The flues should be made with butt-joints, and 
of heavier iron than the shell of the boiler. 



NON-CONDEXSIXG STEAM-EXGINES. 47 

Q. What is a butt-joint? 

A. It is a joint formed by bringing the ends of two 
sections of the flue together and overlapping them on 
the outside and inside with separate pieces of iron. 
This plan of construction gives them additional 
strength, and makes them less liable to collapse. 

Q. What is a collapse ? * 

A. It is a crushing in of a flue or tube by external 
pressure. 

Q. What would be considered a fair allowance of 
grate- and heating-surface to the horse-power in flue 
boilers ? 

A. From 14 to 15 square feet of heating-surface, 
and I square foot of grate-surface. 

Q. What might be called fair evaporation in a 
flue boiler ? 

A. 7 pounds of water to 1 pound of coal. 

Q. What length do you consider most economical 
for flue boilers ? 

A. The length of flue boilers should be about 5 
times their diameter. 

TUBULAK BOILEES. 

Q. What advantage does a tubular boiler possess 
over the cylinder and flue boilers ? 

A. The tubular takes up less room, generates 
steam more rapidly, and requires less fuel ; and the 
tubes are less dangerous than flues on account of 
their small diameter and great strength. 



48 CATECHISM OF HIGH PRESSURE, OR 

Q. What are the disadvantages of tubular boilers ? 

A. First, the tubular boiler is heavy, the first cost 
of them is more than either the flue or the cylinder ; 
second, they are difficult to repair, and almost impos- 
sible to clean ; third, they require great care and at- 
tention to prevent the water from becoming low and 
exposing the tubes to the action of the fire. 

Q. What would you consider the proper length 
for a tubular boiler ? 

A. The length of a tubular boiler should be about 
4 times its diameter. 

Q. What would you consider fair evaporation in 
a tubular boiler ? 

A. The evaporation of 9 pounds of water to 1 
pound of coal. 

Q. What might be called a fair allowance of heat- 
ing- and grate-surface to the horse-power in a tubular 
boiler ? 

A. 14 square feet of heating-surface, } square foot 
of grate-surface. But in the tubular, as in all other 
boilers, the horse-power of the boiler depends upon 
the following conditions : first, the grate-surface ; 
second, the heating-surface ; third, draught ; fourth, 
the qualities of the fuel used ; fifth, the conducting 
powers of the iron ; and sixth, the proper application 
of the steam after it leaves the boiler. 



NON-CONDENSING STEAM-ENGINES. 49 

DOUBLE-DECK BOILEES. 

Q. What do you mean by a double-deck boiler ? 

A. I mean a tubular and cylinder connected to- 
gether by what are called water-necks — the cylinder 
being uppermost and used as a steam-dome. 

Q. What are the advantages of the double-deck 
boiler ? 

A. A double*cleck boiler occupies less space than 
any of the three former kinds of boilers ; it steams 
very economically, and is also more safe than the 
single tubular, because the lower or tubular cylinder 
is entirely free from water. There is very little 
danger of the water becoming low in this kind of a 
boiler. The ends of the tubes are not exposed to the 
action of the fire, as in the single tubular, as the 
draught passes under the boiler and returns through 
the tubes, and re-returns between the tubular and 
cylinder. This boiler seems to have no objectionable 
features, with the exception that the lower or tubular 
section is impossible to clean. It might be said also 
that the boiler is heavy and expensive ; but it pre- 
sents an immense amount of heating-surface. 

LOCOMOTIVE BOILEES. 
Q. What are the advantages and disadvantages of 
the locomotive boiler ? 

A. The advantages are : the locomotive form of 
the boiler is compact and powerful, and, when well 
proportioned to its work, is very economical for fac- 
5 D 



50 CATECHISM OF HIGH PRESSURE, OR 

tory use ; it occupies small space and generates steam 
very rapidly. Its disadvantages are : first, it is expen- 
sive ; second, impossible to clean ; third, it requires 
great care in keeping the water above the tubes and 
crown-sheet. It is also very difficult to repair, and 
where the water is impure soon burns out. 

Q. Are all steam-boilers fired alike ? 

A. No ; some boilers, such as the locomotive, Dim- 
field, and Cornish boilers, are fired internally ; while 
the cylinder, flue, and tubular boilers are fired ex- 
ternally ; though in the last two the heat is applied 
both internally and externally. 

MUD-DEUMS. 

Q. What is a mud-drum ? 

A. A mud-drum is a small cylinder boiler, generally 
24 inches in diameter, connected with the main boiler 
at the bottom, for the purpose of receiving the feed- 
water before it enters the boiler. 

Q. What are the advantages and disadvantages of 
the mud-drum ? 

A. Mud-drums at one time were considered a bene- 
fit, as imparting extra heat, and also retaining the 
sediment carried in by the feed -water. But after 
years of experience in the use of the mud-drum, it 
was found that the drum imparted very little heat to 
the feed-water, and retained nothing but the earthy 
matter that is not injurious to a boiler. But all the 
destructive carbonates that form the hard glassy scale 



NON-CONDENSING STEAM-ENGINES. 51 

were carried into the boiler. Experience showed us 
that the rnud-drum was positively dangerous, on ac- 
count of not receiving sufficient heat to keep the iron 
dry. The corrosion of the mud-drum was very rapid, 
and became dangerous, in many cases before parties 
using them were actually aware of it. Some very 
serious accidents happened through the bursting of 
mud -drums. The mud -drum was generally worn 
out in 5 or 6 years, and the expense of removing the 
old drum and replacing it with a new one was more 
than the benefit derived from its use. The mud- 
drum is fast going out of use. 

BOILEE-HEADS. 

Q. What kinds of material are most commonly 
used for boiler-heads ? 

A. Wrought and cast iron. 

Q. Which kind of material do you consider most 
safe ? 

A. Wrought iron; as it is lighter, possesses greater 
strength, and presents better advantages for bracing 
in boilers of large diameter than cast iron. 

Q. What are the most common shapes for cast- 
iron heads of boilers ? 

A. Flat, concave,, and convex. 

Q. What are the advantages and disadvantages of 
the above-named heads? 

A. First, the flat head should be avoided, like all 
flat surfaces in steam-boilers, because when subjected 



52 CATECHISM OF HIGH PEESSUEE, OR 

to a great strain they are positively dangerous. Sec- 
ond, the concave presents greater strength with less 
metal than the flat head. The only disadvantage we 
know of in the concave is in cases where the flange 
of the head is too deep on the inside, preventing the 
water from coming in contact with the rivets, and 
the boiler is liable to be burned through at that 
point. Third, the convex is not so strong as the con- 
cave, but is very much safer, with the same amount 
of metal, than the flat head. 

BOILEE-SHELLS. 

Q. What thickness of boiler-iron do you consider 
the safest, most durable, and economical for boilers ? 

A. First, to insure safety in shells and flues of 
boilers, the thickness proper to use depends very 
much on the quality of the iron, diameter of boiler, 
and pressure to be carried. Second, as to durability, 
the thickest iron is not always the best, as the outside 
of the sheet becomes burned and crystallized, and in 
most cases gives less wear and satisfaction than a 
thinner gauge. Third, as to economy, thin boilers 
are more economical with fuel, and wear longer, 
provided in all cases that the diameter and the pres- 
sure are in proportion. 

Q. What would you consider the proper thickness 
for all boilers ? 

A. The thickness of boiler-iron for all boilers must 
range between T 7 g and T 3 g of an inch, for the reason 



NON-CONDENSING STEAM-ENGINES. 53 

that i inch iron is almost too thick to be riveted and 
T 3 g is too thin to be caulked. Of course, it will be 
understood that the choice of thickness between these 
two limits will depend on the quality of the iron, di- 
ameter of the boiler, and pressure to be carried, as 
before stated. 

Q. What would you consider the proper thickness 
of iron for a boiler 48 inches in diameter, carrying a 
pressure of 90 pounds to the square inch ? ■ 

A. | of an inch for ordinary brands of iron, but 
i inch of superior iron would be just as strong. 

Q f What do you consider the proper thickness for 
the wrought-iron heads of a boiler 48 inches in di- 
ameter, carrying a pressure of 90 pounds ? 

A. |g or f ; either thickness would be perfectly 
safe. 

Q. What would you consider the proper thickness 
for the tube-sheets and crown-sheets of boilers ? 

A. The thickness of the iron will depend on the 
diameter of the boiler and the quality of the iron, 
but the range for all boilers will be perhaps from f 
to f of an inch thick. 

Q. Is the temperature of thick boiler-plates often 
much higher than that of the steam ? 

A. Yes; thick boiler-plates or tube-sheets are in 
many instances several hundred degrees above the 
temperature of the steam in the boiler, and as a con- 
sequence are extremely dangerous. 
5* 



54 CATECHISM OF HIGH PRESSURE, OR 

Q. Is the pressure the same on all riveted seams 
in boiler-shells ? 

A. No ; the pressure on the longitudinal rivets is 
nearly double that on the curvilinear rivets. 

Q. What do you mean by longitudinal and cur- 
vilinear rivets ? 

A. By longitudinal rivets, I mean the rivets or 
seams that run lengthwise on the boiler ; the curvi- 
linear are those that are around the circumference of 
the shell. 

Q. If the pressure on the longitudinal seams is 
double that on the curvilinear, how can all parts of 
the boiler sustain the same pressure ? 

A. By making the longitudinal seams double 
riveted and the curvilinear single. 

Q. What is the difference in strength between 
single and double riveted seams ? 

A. Single-riveted seams are equal to 56 per cent, 
of the material used, while double riveting is equal 
to 70 per cent. 

Q. What do you mean by " equal to 56 per cent, 
of material used " ? 

A. I mean that the boiler-plates lose 44 per cent, 
of their strength in the process of punching. 

Q. What do you consider the proper diameter for 
rivets of boilers ? 

A. That would depend very much on the diameter 
of the boiler, thickness of iron, and pressure to be car- 
ried. For boilers from 36 to 42 inches diameter, 



NON-CONDENSING STEAM-ENGINES. 55 

and I iron, if single riveted, the rivets ought to be § 
of an inch for curvilinear, and f for the longitudinal ; 
if double riveted, § will answer for both longitudinal 
and curvilinear seams. From T 5 g iron down to T 3 g, 
smaller rivets will answer. 

Q. Which do you consider the best method of riv- 
eting boilers — by hand or by machine ? 

A. For average or thin boiler-plates, hand riveting 
does very well, but for heavy iron, T 7 g or i inch thick, 
machine work is far superior, the power of the ma- 
chine brings the work together far better and with 
less injury to the iron than can be done by hand. 

Q. How should the fibre of the iron be placed to 
give the greatest strength ? 

A. The direction in which the iron is rolled should 
always be placed around the boiler, and not length- 
wise, because in cylindrical boilers the strain in the 
line of the axis is much less than the circumferential 
bursting strain. 

Q. Do you consider it an advantage to drill the 
rivet-holes in boilers instead of punching ? 

A. Yes ; for all first-class work there can be no 
doubt but that all the rivet-holes ought to be drilled, 
on account of the liability of the plates to become 
fractured by the process of punching, causing a great 
reduction in the strength of the boilers. 

Q. Would the same sized rivets answer for punched 
and drilled holes ? 



56 CATECHISM OF HIGH PRESSURE, OR 

A. No ; drilled holes require larger rivets than 
those that are punched. 

Q. How do you explain that ? 

A. Because the shearing strain on the drilled 
holes is far greater than on the punched, as the hole 
is more perfect and sharp, and there is less friction 
between the sheets when drilled. A § rivet will 
stand as much shearing strain in a punched hole as 
a i will in a drilled hole. 

Q. Do you consider the use of the drift-pin ought 
to be dispensed with as much as possible in making 
boilers ? 

A. Yes; a reckless use of the drift-pin has in 
many cases resulted in great injury to the boiler- 
plates ; and there is good reason to believe that such 
injuries as are caused by the drift-pin, often hasten 
the destruction of the boiler. 

Q. What is a drift-pin ? 

A. It is a tapering steel pin introduced into the 
holes in the seams, to bring them into line. 

Q. How do you propose to dispense with the use 
of the drift-pin ? 

A. If the holes are laid off carefully in the sheet, 
and punched with judgment, there will be very little 
need for the drift-pin, as the holes can be straight- 
ened by a flat reamer. Such work will be greatly 
superior to that where the drift-pin is used. 

Q. Do you think it would be any benefit to 



NON-CONDENSING STEAM-ENGINES. 57 

slightly heat the boiler-plates before rolling them to 
form the shell of the boiler ? 

A. Yes ; I think it would add very materially to 
the strength and durability of boilers if the sheets 
were rolled while warm, as the fibre of the iron 
would be drawn out ; while, in the common practice 
of cold rolling, the fibre is crushed and broken. 

Q. Does hammering improve the quality of iron ? 

A. No ; it only hardens it, but at the same time 
renders it more brittle, whilst rolling imparts tough- 
ness. 

Q. What fact is observable when boiler-iron is 
broken suddenly, as in the case of steam-boiler ex- 
plosions ? 

A. It generally presents a crystalline fractured 
appearance ; when, if broken by some slow process, it 
presents a fibrous or silky appearance, — in the first 
case the fibre is fractured, and in the other it is 
drawn out. 

Q. What does the crystalline fracture indicate ? 

A. It indicates hardness, while a fibrous fracture 
is a mark of softness and ductility. The finer and 
more uniform the crystals the higher the quality of 
the iron. 

Q. Is the pressure equal on all sides of the shell 
of a boiler when under steam ? 

A. No ; there is more pressure on the lower than 
on the upper side of a boiler ; as the steam presses 
equally on 'the surface of the water as on the upper 



58 CATECHISM OF HIGH PRESSURE, OR 

side of the boiler, the weight of the water must be 
added to the pressure on the lower side. 

Q. How do you explain that ? 

A. In this way : in a boiler 36 inches in diameter, 
circumference 113 inches, if full of water, the water 
would weigh 441 pounds to the foot in length ; now, 
if the boiler was 20 feet long, the water would weigh 
8820 pounds ; take f of that (which would be about 
the quantity of water in a boiler when under steam) 
and the weight of water would be 5880 pounds, 
which shows the excess of pressure on the lower side 
of the boiler. 

Q. Are the shells and flues of boilers sometimes 
injured by the application of the cold water or 
" Hydrostatic " test ? 

A. Yes ; the shells and flues of boilers are some- 
times injured by a reckless use of the test, and in 
many cases explosions take place soon after the test 
is applied. 

Q. Would the shell and flues of a boiler be 
stronger under a cold water pressure of 70 or 80 
pounds to the square inch than under the same 
steam pressure ? 

A. No ; as iron increases in strength by the appli- 
cation of heat up to 550° Fah., the boiler would be 
stronger under the steam pressure. 

Q. What is the maximum strength of wrought 
iron ? 

A. 60,000 pounds to the square inch at a tern- 



NON- CONDENSING STEAM-ENGINES. 



59 



perature of 550° Fah., or in other words, a bar of 
iron one inch square would stand a tensile strain of 
60,000 pounds. 

A Table deduced from Experiments on Iron Plates for 
Steam-Boilers, by the Franklin Institute, Philadelphia, 

Iron boiler-plate was found to increase in tenacity 
as its temperature was raised, until it reached a tem- 
perature of 550° above the freezing-point, at which 
point its tenacity began to diminish. The following 
table exhibits the cohesive strength at different tem- 
peratures : — 



At 32° to 80° tenacity is 56,000 



66,000 " 

55,000 " 



At 
At 


570° 
720° 


At 


1050° 


At 


1240° 


At 


1317° 



\ 32,000 " 
c 22,000 " 

1 9,000 " 



or one - seventh be- 
low its maximum. 

the maximum. 

the same nearly as at 
32°. 

nearly one -half the 
maximum. 

nearly one -third the 
maximum. 

nearly one-seventh the 
maximum. 



At 3000° wrought iron becomes fluid. 

It will be seen that by the accidental overheating 
of a boiler the tenacity of the iron would soon be- 
come reduced to nearly half its strength. 

The following Table is the result of experiments 
made on different brands of boiler-iron at the Ste- 
vens Institute of Technology. The samples tested 
were taken from lots of iron sent to market bv va- 



60 CATECHISM OF HIGH PRESSURE, OR 

rious manufacturers of boiler-plate, and may be con- 
sidered to represent in most cases an average quality 
of the several grades of iron. 

Thirty-three experiments were made upon iron 
taken from the exploded steam-boiler of the ferry- 
boat Westfield. The following were the results : 

Lbs. per sq. inch 

Average breaking weight 41,653 

16 experiments made upon high grades of American boiler-plate. 

Average breaking weight 54,123 

15 experiments made upon high grades of American flange iron. 

Average breaking weight 42,144 

6 experiments made upon English Bessemer steel. 

Average breaking weight 82,621 

5 experiments made upon best English Lowmoor boiler-plate. 

Average breaking weight 58,984 

6 experiments made upon samples of tank iron from different 

manufacturers. 

Average breaking weight, No. 1 43,831 

No. 2 42,011 

" " " No. 3 41,249 

2 experiments made on iron taken from the exploded steam- 
boiler of the Red Jacket. 
Average breaking weight 49,000 

It will be noticed that the above experiments re- 
veal a great variation in the strength of boiler- 
plate of different grades of iron, and furnish conclu- 
sive evidence that the tensile strength of boiler-iron 
ought to be taken at 50,000 pounds to the square 
inch, instead of 60,000. 

Q. What reduction in length does wrought iron 
undergo when subjected to compression? 

A. It is reduced .0001 of its length by every ton 



non-condensing steam-engines. 61 

per square inch up to 13 tons, beyond which the 
amount of compression increases more rapidly. 

STEEL BOILEES. 

In stiffness or rigidity, as well as high ultimate re- 
sistance and good conducting powers, steel presents 
many advantages, as a substitute for iron, in the con- 
struction of boilers. Some of the largest locomotive 
establishments in this country are using steel for boil- 
ers. The substitution of steel for iron in the manu- 
facture of boilers is rapidly spreading in all the 
countries of Europe. 

Q. What advantages do steel boilers possess over 
iron ? 

A. The advantages of steel boilers are : first, they 
are lighter ; second, they are stronger ; third, their 
conducting powers are higher. For instance, a steel 
boiler 48 inches in diameter and i inch thickness 
of sheets is as strong as an iron boiler of the same 
diameter and I inch thickness of iron, and w r ill evapo- 
rate 25 per cent, more water with the same amount 
of fuel in a given time. Steel boilers are more free 
from incrustation and corrosion than iron, on account 
of the density and compactness of the material. But 
in the manufacture of steel boilers great care should 
be taken that the plates are not fractured in punching. 
6 



62 CATECHISM OF HIGH PRESSURE, OR 

INTERNAL AND EXTERNAL PRESSURES. 

An important difference of condition, never to be 
lost sight of in boiler-work, is that all internal pres- 
sure tends to preserve the symmetry of form of the 
boiler, while all external pressure tends to destroy 
that symmetry, which, if altered at all, places the 
boiler in new conditions, likely to end in sudden 
destruction. 

Q. If pressure is exerted on the internal or exter- 
nal surface of the cylinder, is the effect the same in 
both cases ? 

A, No ; when pressure is exerted within a tube or 
cylinder, the tendency of the strain is to cause the 
tube to assume the true cylindrical form ; but when 
pressure is exerted on the outside of the tube, the 
tendency of that pressure is to crush the tube or 
flatten it ; as it is a well-known fact that iron of 
any strength when formed into a tube will require a 
much greater strain to tear it asunder than it would 
take to crush it. 

Q. How do you explain that? 

A. In this way : a thin hoop of iron will resist a 
very great amount of tearing force, but if that same 
hoop or circle be placed as a prop under half the 
weight that was exerted to tear it apart, it would be 
crushed flat. 

Q. What is the difference between external and 
internal strain? 



NON-CONDENSING STEAM-ENGINES. 63 

A. Internal is a tearing strain, whilst external is 
a crushing strain; and flues and tubes of boilers 
are nothing but a series of props, and a constant ten- 
dency of the pressure is to flatten the tube or flue, 
and cause it to collapse. 

Q. What is a collapse ? 

A. It is the crushing or flattening of a flue by over- 
pressure, and is often attended with terrible results. 

Q. What is an explosion ? 

A. It is an accident that takes place in most cases 
from the water becoming low, when, through igno- 
rance or recklessness, cold water is admitted to the 
boiler, and explosion takes place. 

Q. What is a burst ? 

A. It is an accident that occurs from over-pressure, 
and is generally more terrible in effect than either an 
explosion or a collapse. 

Q. Why should the burst be more destructive than 
the explosion ? 

A. Because, in the case of the explosion, the te- 
nacity of the iron is partly destroyed by being over- 
heated ; while, in the case of the burst, the iron is torn 
apart at its maximum strength. 

Q. What is the best preventive against explo- 
sions, bursts and collapses ? 

A. Never tax the boiler above a safe working 
pressure; keep it clean and in good repair, the 
safety-valve in good order, and the water at all times 
at the proper level. 



64 CATECHISM OF HIGH PRESSURE, OR 

Q. What part gives way first when a boiler bursts ? 

A. A boiler gives way in the weakest place. 

Q. What should be considered the strength of a 
boiler ? 

A. The weakest part of the boiler. 

Q. How do you explain that ? 

A. In this way : if some parts of a boiler are I 
of an inch thick, whilst other parts are not more 
than |, the pressure carried on the boiler should 
be that which would be safe for T 3 g of an inch. 

KULES. 

Rule for finding the quantity of water in a boiler 
in cubic inches. 

Multiply the internal area of the head of the boiler, 
in inches, by the length of the boiler in inches, the 
product w T ill be the number of cubic inches of water 
in the boiler. Divide this product by 1728, and the 
quotient will be the number of cubic feet of water in 
the boiler. 

Q. In what way do riveted joints give way? 

A. Either by shearing off the rivets in the middle 
of their length, or by tearing through one of the plates 
in the line of the rivet-holes. In a perfect joint, the 
rivets should be on the point of shearing just as the 
plates were about to tear ; hence, in good practice, it 
is an established rule to employ a certain number of 
rivets to the linear foot. If these are placed in a 
single row, the rivet-holes so nearly approach each 



NON-CONDENSING STEAM-ENGINES. 65 

other that the strength of the plates is much reduced ; 
but if they are arranged in two lines, a greater num- 
ber ma) 7 be used, and yet more space left between 
the holes, and greater strength and stiffness imparted 
to the plates at the joint. 

It is perfectly obvious that in perforating a line 
of holes along the edge of a plate, we must greatly 
reduce its strength. 

When this great deterioration of strength at the 
joint is taken into account, it cannot but be of the 
greatest importance that in structures subjected 
to such violent strains as steam-boilers are, the 
strongest method of riveting should be adopted. 

Rule for finding safe external pressure on boiler- 
flues. 

Multiply the square of the thickness of the iron 
by the constant whole number 806,300 ; divide this 
product by the diameter of the flue in inches ; multi- 
ply the quotient by the length of the flue in feet ; 
multiply this product by 3. 

Rule for finding safe working pressure of any boiler. 

Multiply the thickness of the iron by .56 (or .70, 
according as the boiler is single or double riveted) ; 
multiply this product by 10,000 (safe load) ; then 
divide this last product by the internal radius : the 
quotient will be the safe working pressure in pounds 
per square inch. 

Five times the safe working pressure is the burst- 
ing pressure. 

6* E 



66 



CATECHISM OF HIGH PRESSURE, OR 



The experiments of Mr. Fairbairn and others have 
established the following relative strengths as the 
value of plates with either single or double riveted 
joint. 



ji 



. © o o © © © © 




Taking the strength of the plate at 100 

The strength of the double-riveted joint would then be . -. . 70 
And the strength of the single-riveted joint 56 



The following Table will show the safe working 
pressure for boilers of different diameters and differ- 
ent thicknesses of iron, according to Fairbairn's 
experiments. 

For internal pressure, I of the value of ordinary 
boiler-iron, or 50,000 pounds for the inch of section, 
is taken to be safe, while in external pressures ^ is 
taken. 



/ 



NON-CONDENSING STEAM-ENGINES. 

TABLE. 

INTERNAL PRESSURES. 



67 



Birmingham "SVire 
Gauge. 


3 

8 


00 





1 


2 


Thickness of Iron. 


.375 


.358 


.340 


.300 


.284 






3 


| Scant. 


U 


5 

16" 


9 
32 


External 


In. 

24 


180.65 


172.20 


163.29 


143.59 


135.75 


Diameter. 


26 


166.34 


158.58 


150.39 


132.28 


125.08 




28 


15413 


146.96 


139.38 


122.63 


115.95 




30 


143.59 


136.92 


129.88 


114.29 


108.07 




32 


134.40 


• 128.17 


121.58 


107.01 


101.20 




34 


126.31 


120.47 


114.29 


100.60 


95.14 




36 


119.15 


113.64 


107.81 


94.92 


89.77 


Longitudinal 


38 


112.75 


107.54 


102.04 


89.84 


84.98 


Seams, 


40 


107.01 


102.07 


96.85 


85.28 


80.67 


Single 


42 


101.81 


97.12 


92.11 


81.16 


76.77 


Riveted. 


44 


97.11 


92.63 


87.90 


77.42 


73.24 




46 


92.82 


88.54 


84.02 


74.01 


70.01 




48 


88.89 


84.80 


80.47 


70.89 


67.06 




50 


85.28 


81.36 


77.21 


68.02 


64.35 




52 


81.95 


78.18 


74.20 


65.37 


61.84 




54 


78.87 


75.25 


71.42 


62.92 


59.53 




56 


76.02 


72.53 


68.84 


60.65 


57.38 




58 


73.36 


70.00 


66.43 


58.54 


55.38 




60 


70.89 


67.63 


64.19 


56.57 


53.52 




62 


68.57 


65.43 


62.10 


54.72 


51.78 




64 


66.40 


63.36 


60.14 


53.00 


50.15 




66 


64.37 


61.42 


58.30 


51.38 


48.61 




68 


62.45 


59.59 


56.57 


49.85 


47.17 




70 


60.65 


57.87 


54.93 


48.41 


45.81 




72 


58.95 


56.25 


53.39 


47.06 


44.53 




74 


57.34 


54.71 


51.94 


45.78 


43.32 




76 


55.81 


53.26 


50.56 


44.56 


42.17 




78 


54.37 


51.88 


49.25 


43.41 


41.08 




80 


53.00 


50.57 


48.01 


42.32 


40.04 



68 



CATECHISM OF HIGH PRESSURE, OR 



TABLE. 

INTERNAL PEESSUEES. — (Continued.) 



Birmingham 
Wire Gauge. 


3 


4 


5 


6 


7 


8 


Thickness of 


.259 


.238 


.220 


.203 


.180 


.165 


Iron. 


i Full. 


4 Scant. 


7 


2%Full. 


3 6 2 Sc't. 


B 5 2 Full. 


External 


In. 

24 


123.53 


113.31 


104.58 


96.36 


85.28 


78.07 


Diameter 


26 


113.84 


104.44 


96.40 


88.83 


78.63 


71.99 




28 


105.55 


96.85 


89.40 


82.39 


72.94 


66.79 




30 


98.39 


90.29 


83.36 


76.83 


68.02 


62.29 




32 


92.14 


84.56 


78.07 


71.96 


63.72 


58.35 




34 


86.64 


79.51 


73.42 


67.68 


59.93 


54.89 




36 


81.75 


75.04 


69.29 


63.88 


56.57 


51.81 


Long. 


38 


77.39 


71.04 


65.60 


60.48 


53.56 


49.06 


Seams. 


40 


73.47 


67.44 


62.29 


57.42 


50.86 


46.58 


Single 


42 


69.93 


64.19 


59.29 


54.66 


48.41 


44.35 


Riveted. 


44 


66.71 


61.24 


56.57 


52.15 


46.20 


42.32 




46 


63.78 


58.55 


54.08 


49.87 


44.17 


40.46 




48 


61.09 


56.09 


51.81 


47.77 


42.32 


38.77 




50 


58.62 


53.82 


49.72 


45.84 


40.61 


37.21 




52 


56.35 


51.74 


47.79 


44.07 


39.04 


35.77 




54 


54.24 


49.80 


46.00 


42.42 


37.58 


34.43 




56 


52.28 


48.01 


44.35 


40.90 


36.23 


33.20 




58 


50.46 


46.34 


42.81 


39.48 


34.98 


32.04 




60 


48.77 


44.78 


41.37 


38.15 


33.80 


30.97 




62 


47.18 


43.33 


40.03 


36.91 


32.71 


29.97 




64 


45.69 


41.96 


38.77 


35.75 


31.68 


29.02 




66 


44.30 


40.68 


37.58 


34.66 


30.71 


28.14 




68 


42.99 


39.48 


36.47 


33.64 


29.80 


27.31 




70 


41.75 


38.34 


35.42 


32.67 


28.95 


26.53 




72 


40.58 


37.27 


34.43 


31.76 


28.14 


25.78 




74 


39.48 


36.25 


33.50 


30.89 


27.38 


25.08 




76 


38.43 


35.29 


32.61 


30.08 


26.65 


24.42 




78 


37.44 


34.38 


31.77 


29.30 


25.96 


23.79 




80 


36.49 


33.52 


30.97 


28.56 


25.31 


23.20 



NON-CONDENSING STEAM-ENGINES. 



69 



TABLE. 

INTERNAL PRESSURES. — (Continued.) 



Birmingham Wire 
Gauge. 


3 

8 


00 





1 


2 


Thickness of Iron. 


.375 

3 


.358 


.340 
ii 


.300 

5 


.284 

9 




"8 


-g Scant. 


32 


16 


?2 


External 


In. 

24 


225.81 


215.26 


204.12 


179.49 


169.67 


Diameter. 


26 


207.93 


198.23 


187.91 


165.35 


156.34 




28 


192.66 


183.70 


174.23 


153.28 


144.94 




30 


179.49 


171.15 


162,35 


142.86 


135.09 




32 


168.00 


160.21 


151.98 


133.76 


126.49 


Longitudinal 


34 


157.89 


150.58 


142.86 


125.75 


118.93 


Seams, 


36 


148.94 


142.05 


134.77 


118.64 


112.21 


Double 


38 


140.94 


134.43 


127.55 


112.30 


106.22 


Riveted. 


40 


133.76 


127.58 


121.06 


106.60 


100.83 


Curvilinear 


42 


127.27 


121.40 


115.20 


101.45 


95.96 


Seams, 


44 


121.39 


115.79 


109.88 


96.77 


91.55 


Single 


46 


116.02 


110.68 


105.03 


92.51 


87.52 


Eiveted. 


48 


111.11 


106.00 


100.59 


88.61 


83.83 




50 


106.19 


101.70 


96.51 


85.02 


80.43 




52 


102.44 


97.73 


92.75 


81.71 


77.31 




54 


98.59 


94.10 


89.27 


78.69 


74.41 




56 


95.02 


90.66 


86.04 


75.81 


71.73 




58 


91.70 


87.49 


83.04 


73.17 


69.23 




60 


88.61 


84.54 


80.24 


70.71 


66.90 




62 


85.71 


81.78 


77.63 


68.40 


64.72 




64 


83.00 


79.17 


75.17 


66.25 


62.68 




66 


80.46 


76.78 


72.87 


64.22 


60.77 




68 


78.07 


74.49 


70.71 


62.31 


58.96 




70 


75.81 


72.34 


68.67 


60.52 


57.26 




72 


73.68 


70.31 


66.74 


58.82 


55.66 




74 


71.67 


68.39 


64.92 


57.22 


54.15 




76 


69.77 


66.60 


63.19 


55.70 


52.71 




78 


67.96 


64.85 


61.56 


54.26 


51.35 




80 


66.25 


63.22 


60.01 


52.90 


50.06 



70 



CATECHISM OF HIGH PRESSURE, OR 



TABLE. 

INTERNAL PRESSURES.— (Continued.) 



Birmingham 
"Wire Gauge. 


3 


4 


5 


6 


7 


8 


Thickness 


.259 


.238 


.220 


.203 


.180 


.165 


of Iron. 


% Full. 


f- Scant. 


7 
32 


F2 ^ll. 


^o Scant. 


3 5 ^Full. 


Ext'l 


Io. 

24 


154.42 


141.64 


130.73 


120.45 


106.60 


97.59 


Diam. 


26 


142.30 


130.54 


120.50 


111.04 


98.21 


89.99 




28 


131.94 


121.06 


111.76 


102.99 


91.17 


83.48 




30 


122.99 


112.86 


104.19 


96.03 


85.02 


77.86 




32 


116.32 


105.70 


97.59 


89.95 


79.65 


72.94 


Long. 


34 


108.30 


99.39 


91.78 


84.60 


74.91 


68.61 


Seams, 


36 


102.19 


93.80 


86.61 


79.84 


70.71 


64.76 


Doub'e 


38 


96.74 


88.80 


82.00 


75.60 


66.95 


61.32 


Kiv't'd 


40 


91.84 


84.30 


77.86 


71.78 


63.57 


58.23 


Curvil. 


42 


87.41 


80.24 


74.11 


68.33 


60.52 


55.44 


Beams, 


44 


83.39 


76.56 


70.71 


65.19 


57.75 


52.90 


Single 


46 


79.72 


73.19 


67.60 


62.33 


55.22 


50.58 


Kiv't'd 


48 


76.37 


70.11 


64.76 


59.71 


52.90 


48.46 




50 


73.28 


67.28 


62.11 


57.31 


50.77 


46.51 




52 


70.43 


64.67 


59.74 


55.08 


48.80 


44.71 




54 


67.80 


62.25 


57.51 


53.40 


46.98 


43.04 




56 


65.35 


60.01 


55.44 


51.12 


45.29 


41.50 




58 


63.07 


57.92 


53.51 


49.35 


43.72 


40.06 




60 


60.96 


55.98 


51.71 


47.69 


42.25 


38.71 




62 


58.98 


54.16 


50.03 


46.14 


40£8 


37.46 




64 


57.12 


52.45 


48.46 


44.69 


39.60 


36.28 




66 


55.37 


50.85 


46.98 


43.33 


38.39 


35.18 




68 


53.73 


49.35 


45.59 


42.05 


37.26 


34.14 




70 


52.19 


47.93 


44.28 


40.84 


36.19 


33.16 




72 


50.73 


46.59 


43.04 


39.70 


35.18 


32.23 




74 


49.35 


45.32 


41.87 


38.62 


34.22 


31.36 




76 


48.04 


44.11 


40.76 


37.60 


33.32 


30.53 




78 


46.80 


42.98 


39.71 


36.63 


32.46 


29.74 




80 


45.62 


41.90 


38.71 


35.71 


31.64 128.99 



NON-CONDENSING STEAM-ENGINES. 71 

FOAMING IN STEAM-BOILERS. 

Q. What is the cause of foaming in steam-boilers ? 

A. Foaming in steam-boilers might be attributed 
to different causes. First, to the boiler not having 
a sufficient amount of steam-room, so that whenever 
the valve opens to admit steam to the cylinder, the 
pressure on the surface of the water- is lessened, 
allowing the water to rise up from the bottom of the 
boiler. Second, foaming is sometimes caused by the 
foul condition of the boiler ; but in such cases it will 
be easy to discover the cause, as the water in the glass 
gauge will appear quite muddy. Third, foaming is 
caused by the presence of any substance of a soapy 
or greasy nature in the water. But whatever may 
be the cause of foaming, it is always attended with 
great danger to the boiler and a certain amount of 
injury to the engine. 

In all cases where a boiler foams badly, the water 
is lifted from the fire-surface of the boiler, and allows 
the iron to burn ; also, the mud and water from the 
boiler are carried over with the steam to the cylinder, 
occupying the clearance between the piston and the 
head of the cylinder ; not only destroying the surface 
of the cylinder by the grit and dirt, but in many 
cases causing the fracture of the cylinder-head. 

Q. What is the best preventive against foaming ? 

A. The best preventive against foaming is : 
First, a clean boiler. Second, pure water. Third, a 



72 CATECHISM OF HIGH PPwESSUEE, OR 

sufficient amount of steam-room. Fourth, a steam- 
pipe well proportioned to the size of the cylinder. 

BUST. 

Q. From what cause does the decay of iron arise ? 

A. From the joint action of air and water, the 
oxygen from which combines with the iron and forms 
a hydrate called rust. 

Q. What parts of steam-boilers are most liable to 
corrode or burn out ? 

A. The parts directly over the fire when coated 
with scale, and those exposed to dampness. 

PATENT STEAM-BOILERS. 

There is hardly anything connected with steam- 
engineering that is so uncertain as the records of the 
results of experiments made with patent boilers. A 
great many new designs have been brought forward 
and tested, but the results have been either imper- 
fectly recorded or kept secret by men who did not 
care to announce that they had been unsuccessful. 
It is to be regretted that steam users and the public 
know so little of the evaporative capacity of patent 
boilers ; even such information as we do have is very 
imperfect, as those who supply it are almost inva- 
riably inaccurate. First, because they do not know 
how to secure accuracy; second, because they de- 
ceive themselves ■ and, third, because they deceive 
the public. 



NON-CONDEXSING STEAM-ENGINES. 78 

There are three great objects to be attained in de- 
signing a steam-boiler ; in the first place it should be 
safe ; in the second, it should be economical with 
fuel ; in the third, it should steam well. Now, as 
regards patent boilers, there is information wanted 
concerning them on the three above points. 

THE SAFETY-VALVE. 

The form and construction of this indispensable 
adjunct to the steam-boiler are of the highest im- 
portance, not only for the preservation of life and 
property, which would in the absence of this means 
of safety be constantly jeopardized, but also to secure 
the durability of the steam-boiler itself. 

Increasing the pressure to a dangerous degree 
would be impossible in any boiler, if the safety-valve 
were what it is supposed to be, — a perfect means for 
liberating all the steam which a boiler may produce 
with the fires in full blast, and all other means for 
the escape of steam closed. Until such a safety- 
valve shall be devised and adopted into general use, 
safety from gradually increasing pressure must de- 
pend on the attention and watchfulness of the en- 
gineer. 

We have decidedly too much theory on the safety- 
valve, and most of this theory is the merest vagary, 
which it is impossible to harmonize with experience 
and sound practice. All that the safety-valve needs 



74 CATECHISM OF HIGH PRESSURE, OR 

to make it what it was intended to be, is, first, an 
orifice proportioned to the grate - surface ; second, 
simplicity of construction ; third, directness of action. 

Q. "What is the object or use of the safety-valve ? 

A. It is a valve intended to relieve the boiler from 
extra pressure, and prevent bursting, collapse or 
explosion. 

Q. What do you consider a proper proportion for 
the safety-valve of a boiler ? 

J.. The area of the safety-valve should be \ square 
inch to each square foot of grate-surface. 

Q. Will this amount of opening of safety-valve be 
safe for any ordinary pressure ? 

A. Yes ; it will be safe for any pressure from 10 
pounds to the square inch up to 100 pounds. 

Q. Is an enlargement of the safety-valve greatly 
beyond what is customary in common practice, dan- 
gerous ? 

A. Yes ; if such a safety-valve by any accident 
should be knocked or lifted suddenly from its seat, it 
would probably cause the destruction of the boiler. 

Q. Should every steam-boiler have two safety- 
valves ? 

A. No ; one safety-valve of suitable proportions, 
and in good order, is sufficient. 

Q. How should the safety-valve be kept or cared 
for? 

-4. It should always be kept as free as possible from 
dust and ashes, and all its working parts in good order. 



NON-CONDENSING STEAM-ENGINES. 75 

Q. How often should the safety-valve be moved ? 

A. At least once a day, more particularly in the 
morning. 

Q. Why should the safety-valve be moved in the 
morning ? 

A. So as to be sure that it is in good working order 
before starting the fire. 

Q. What are the most important principles to 
be adhered to in the construction of the safety- 
valve ? 

A. Simplicity of construction, directness and free- 
dom of action. 

Q. Does the safety-valve become worn and leaky 
by the continual action of the steam ? 

A. Yes ; all safety-valves become leaky, and ought 
to be ground carefully on their seats. 

Q. What is the best material to use for grinding 
safety-valves ? 

A. Pulverized glass, grit of grinding-stones, or 
fine emery. 

Q. Should safety-valves be constructed with loose 
or vibratory stems ? 

A, Yes ; as the rigid or solid stem is apt to be- 
come jammed by the canting of the lever and weight, 
and in such cases the higher the pressure the more 
difficult is the action of the valve. 

Q. Is the marking on safety-valves sometimes 
incorrect ? 

A. Yes ; decidedly so. 



76 



CATECHISM OF HIGH PRESSURE, OR 



Q. How can you tell whether the safety-valve lever 
is marked correctly or not ? 
A. By calculation. 




B, lever. A, short arm of lever. S S, stem. V, valve. G, guide. W. 
weight. 



EULES. 

Rule for finding the weight necessary to put on a 
lever, when the area of valve, pressure, etc., are known. 

Multiply the area of valve by the pressure in 
pounds per square inch ; multiply this product by 
the distance of the valve from the fulcrum ; multi- 
ply the weight of lever by one-half its length (or its 
centre of gravity) ; then multiply the weight of valve 
and stem by their distance from the fulcrum ; add 
these last two products together, and subtract their 
sum from the first product, and divide the remainder 
by the length of lever ; the quotient will be the weight 
of the ball. 



/ 



NON-CONDENSING STEAM-ENGINES. 77 



Example. 






Area of valve, 


7 sq. in. 


60 lbs. 9 lbs. 6 lbs. 


Pressure, 


60 lbs. 


7 in. 12 in. 3 in. 
420 lbs. 108 lbs. 18 lbs. 


Fulcrum, 


3 in. 


3 in. 18 lbs. 
1260 lbs. 126 lbs. 


Length of lever, 


24 in. 


126 lbs. 
24)1134 lbs. 


Weight of lever, 


9 lbs. 


47.25 lbs. weight of ball, 



Weight of valve and stem, 6 lbs. 

Rule for finding the Pressure per Square Inch when the 
Area of Value, Weight of Ball, etc., are known. 
Multiply the weight of ball by length of lever, and 
multiply the weight of lever by one-half its length, 
(or its centre of gravity;) then multiply the 
weight of valve and stem by its fulcrum. Add 
these three products together. This sum, divided by 
the product of the area of valve, and its distance 
from the fulcrum, will give pressure in pounds per 
square inch. 

Example. 

Area of valve, 9 sq. in. 60 lbs. 20 lbs. 5 lbs. 

Fulcrum, 4 in. 36 in. 18 in. 4 in. 

Length of lever, 36 in. 2160 lbs. 360 lbs. 20 lbs. 

Weight of lever, 20 lbs. 360 lbs. 

Weight of ball, 60 lbs. 20 lbs. 9 in. 

Weight of valve | 5 ibs. 36)2680 lbs. 4 in. 

and stem, i , — . 

70.55 lbs. 36 in. 

Pressure per sq. in. 



78 CATECHISM OF HIGH PRESSUEE, OR 

Rule for finding the Area of a Circle when the Diameter 
is given. 
Multiply the square of the diameter by the deci- 
mal .7854. 

Example. Diameter, 3 inches, 3 .7854 

3 9 

9 sq. in. 70.686 sq. in. — area. 

Q. How do you square a diameter ? 

A. Any diameter multiplied by itself is squared ; 
as, for instance, 10 squared equals 100. 

Q. Why do you multiply the square by .7854 ? 

A, By squaring the diameter we get square inches, 
and if we multiply by .7854, we get circular inches. 

Q. What is the difference between circular and 
square inches? 

A. A circular inch is .7854 part of the square 
inch. 

Q. What do you mean by the word " area " ? 

A. By area we mean the amount of surface ex- 
posed to the action of the steam. 



NON-CONDENSING STEAM-ENGINES. 



79 



A TABLE FOR SAFETY-VALVES. 

Containing the Circumferences and Areas of Circles from 
Y 1 ^ of an inch to 4 inches. 





Circumfer- 






Circumfer- 




Diameter. 


ence. 


Area. 


Diameter. 


ence. 


Area. 


A 


.1963 


.0030 


2 in. 


6.2832 


3.1416 


1 
8 


.3927 


.0122 


i 

T6" 


6.4795 


3.3411 


A 


.5890 


.0276 


1 

8 


6.6759 


3.5465 


A 


.7854 


.0490 


3 
1 6 


6.8722 


3.7582 


.9817 


.0767 


1 
4" 


7.0686 


3.9760 


3 

8 


1.1781 


.1104 


5 
1 6 


7.2649 


4.2001 


T% 


1.3744 


.1503 


3 

8 


7.4613 


4.4302 


1 


1.5708 


.1963 


_7_ 
1 6 


7.6576 


4.6664 


A 


1.7671 


.2485 


1 
2 


7,8540 


4.9087 


5 

8 


1.9635 


.3068 


9 
1 6 


8.0503 


5.1573 


11 

1 6 


2.1598 


.3712 


5 

8 


8.2467 


5.4119 


3 

4 


2.3562 


.4417 


ik 


8.4430 


5.6727 


13 
3 6 


2.5525 


.5185 


3 


8.6394 


5.9395 


.7 


2.7489 


.6013 


it 


8.8357 


6.2126 


1~5 
1 6 


2.9452 


.6903 


i 


9.0321 


6.4918 








15 
16 


9.2284 


6.7772 


1 in. 


3.1416 


.7854 








A 


3.3379 


.8861 


3 in. 


9.4248 


7.0686 


i 

8" 


3.5343 


.9940 


i 

T6" 


9.6211 


7.3662 


3 
1 6 


3.7306 


1.1075 


1 

"8 


9.8175 


7.6699 


1 

4 


3.9270 


1.2271 


A 


10.0138 


7.9798 


A 


4.1233 


1.3529 


1 
4" 


10.2102 


8.2957 


3 
8 


4.3197 


1.4848 


A 


10.4065 


8.6179 


A 


4.5160 


1.6229 


f 


10.6029 


8.9462 


i 


4.7124 


1.7671 


A 


10.7992 


9.2806 


9 
T6" 


4.9087 


1.9175 


1 
2 


10.9956 


9.6211 


5 

8 


5.1051 


2.0739 


9 

T6" 


11.1919 


9.9678 


11 
1 6 


5.3015 


2.2365 


f 


11.3883 


10.3206 


3 

4 


5.4978 


2.4052 


a 


11.5846 


10.6796 


it 


5.6941 


2.5801 


i 


11.7810 


11.0446 


1 


5.8905 


2.7611 


a 


11.9773 


11.4159 


it 


6.0868 


2.9483 


i 


12.1737 


11.7932 








15 
T6 


12.3700 


12.1768 








4 in. 


12.5664 


12.5664 



For larger Areas, see Table for Cylinders, page 183. 



80 CATECHISM OF HIGH PRESSURE, OR 

FEED-WATER HEATERS. 

The waste of fuel and danger arising from the 
rapid incrustation of steam-boilers from the deposit 
of mineral substances of impure water are well 
known ; and the damage done to sheets and rivets by 
overheating, in consequence of heavy deposits of 
mineral substances, is one of the causes which pro- 
duce explosions in steam-boilers, causing, as they do, 
terrible destruction and loss of life. He whose in- 
ventive genius and mechanical skill contribute to 
avert such disasters by purifying the feed-water for 
steam-boilers, will, in point of safety and economy, 
confer a boon on mankind. 

The saving in fuel that might be effected by 
thoroughly heating the feed- water — by means of the 
exhaust - steam in a properly constructed heater — 
would be immense, which will be seen from the fol- 
lowing facts : — 

A pound of feed-water entering a steam-boiler at 
a temperature of 50° Fah., and evaporating into 
steam of 60 pounds pressure, requires as much heat 
as would raise 1157 pounds of water 1 degree. A 
pound of feed-water raised from 50° Fah. to 220 
Fah., requires 987 thermal units of heat ; which, if 
absorbed from exhaust-steam passing through a heater, 
would be a saving of 15 per cent, in fuel. Feed- 
water, at a temperature of 200° Fah., entering a 
boiler, as compared in point of economy with feed- 



NON-CONDENSING STEAM-ENGINES.* 



81 



water at 50° Fah., would effect a saving of over 13 
per cent, in fuel ; and with a well -constructed heater 
there ought to be no trouble in raising the feed- water 
to a temperature of 212° Fah. 




82 CATECHISM OF HIGH PRESSURE, OR 

STILWELL'S PATENT IMPROVED LIME-EX- 
TRACTING HEATER AND FILTER 
COMBINED. 

Has obtained a world-wide reputation as the only 
lime-extracting heater extant that will positively and 
entirely prevent incrustation in steam-boilers. It is 
indispensable to an economical use of steam, and does 
its work in the only safe and rational manner, by 
removing all impurities from the feed-water before it 
enters the boilers. 

Explanation of Cut. 

A. — Steam enters the heater, and is divided into 
two currents. B. — Steam escapes from the heater. 
J. — Hot water leaves heater, a. — Overflow - cup 
suspended on end of cold-water pipe. bbbb. — Re- 
movable shelves or depositing surfaces, c. — Filter- 
ing chamber, to be filled with any suitable filtering 
material. The feathered arrows indicate the course 
of the steam, and the plain arrows the course of the 
water. 

The device is claimed to be an established success, 
over 3000 being now at work. We are informed 
that it has been fully tested over a period of 9 years, 
and that it is guaranteed by its makers to completely 
prevent incrustation. 

They are manufactured by the Stilwell & Bierce 
Manufacturing Company, Dayton, Ohio. 



X0X-C0XDEXSIXG STEAM-EXGIXES. 83 

FUEL. 

Q. What are the constituents of coal ? . 

A. The chief constituent is carbon. 

Q. How much carbon does good coal contain ? 

A. About 90 per cent, and 10 per cent, of earthy- 
matter. 

Q. Are there any other gases in coal except 
carbon ? 

A. Yes ; hydrogen, nitrogen, and sulphur in small 
quantities. 

Q. How much heat does 1 pound of pure carbon 
yield in burning ? 

A. 14,000 units. 

Q. How much heat does 1 pound of good coal, 
containing 90 per cent, of carbon, produce ? 

A. It produces in burning about 13,000 units of 
heat. 

Q. What is the mechanical equivalent of 13,000 
units ? 

A. 10,036,000 pounds ; that is to say, 10,036,000 
pounds raised 1 foot high. 

Q. How much air does it require to burn 1 pound 
of coal ? 

A. 240 cubic feet. 

Q. How much air does it require to burn 100 
pounds of coal ? 

A. 15,524 cubic feet of air. 

Q. What is the difference between anthracite and 
bituminous coal ? 



84 CATECHISM OF HIGH PRESSURE, OR 

A. Anthracite coal consists of about 90 per cent, 
of carbon, and bituminous about 80 per cent. 

Q. What is the difference between anthracite coal 
and good pine wood ? 

A. 1 pound of good anthracite coal will evaporate 
as much water as 2 § pounds of wood. 

Q. What is the difference between anthracite coal 
and coke? 

A. Good coke will evaporate more water than the 
best anthracite coal. 

FIRE. 

Q. What is fire? 

A. It is the rapid combustion of the constituent 
elements of organic matter. 

Q. What are the causes which originate this rapid 
decomposition of organic matter? 

A. Fire sometimes occurs without any visible 
cause when materials are in a favorable position, and 
under such circumstances is called spontaneous com- 
bustion. 

Q. Is there any other cause from which fire origi- 
nates? 

A. Yes; fire is sometimes induced by friction, 
sometimes kindled by electricity ; but the mode in 
which it is most commonly propagated is from the 
combustion of other matter that has been already 
ignited. 



NON-CONDENSING STEAM-ENGINES. 



85 



TABLE. 

Showing the Total Heat of Combustion of Various Fuels. 

Total heat of 
combustion 
c-i in lbs. water 
r,,^o frnm 9i 90 heated 1° 
Fah. 



Charcoal 

Charred peat.. 

Coke — good .. 

" mean . 

bad.... 



Coal: 

Anthracite 

Hard bituminous — hardest. 
" softest... 

Coking coal. 

Cannel coal 

Long flaming splint coal 

Lignite 



Peat: 
Perfectly air-dry 

Containing 25 per cent, water., 



Wood: 
Perfectly air-dry 

Containing 25 per cent, water.. 





Evapora- 


Equiva- 


tive power 


lent in 


in lbs.water 


pure 


from 212° 


carbon. 


Fah. 


0.93 


14.00 


0.80 


12.00 


0.94 


14.00 


0.88 


13.20 


0.82 


12.30 


1.05 


15.75 


1.06 


15.90 


0.95 


15.25 


1.07 


16.00 


1.04 


15.60 


0.91 


13.65 


0.81 


12.15 


0.66 


10.00 




7.75 


0.50 


7.50 




5.80 



13,500 
11,600 
13,620 

12,760 
11,890 



15,225 
15,370 
13,775 

15,837 
15,080 
13,195 
11,745 



9,660 
7,000 



7,245 
5,600 



Remark. — In a boiler of fair construction, a pound of coal 
will convert 9 pounds of water into steam. Each pound of this 
steam will represent an amount of energy, or capacity for per- 
forming work, equivalent to 74:6,666 footpounds, or for the 
whole 9 pounds, 6,720,000 footpounds. In other words, 1 pound 
of coal has done as much work in evaporating 9 pounds of water 
into 9 pounds of steam as would lift 2,232 tons 10 feet high. 



CHIMNEYS. 

Probably there is nothing connected with the gen- 
eration of steam and utilization of heat so imperfectly 
8 



86 CATECHISM OF HIGH PRESSURE, OR 

understood, at present, as the quantity of air that 
passes through the furnaces of boilers under varying 
conditions of draught ; it has been generally assumed, 
from experiment in common practice, that double the 
amount of air necessary for complete combustion of 
the fuel passes through the furnace. 

Experiments are greatly needed to determine the 
state of combustion in varying dimensions of chim- 
neys, as well as the quantity of air drawn through 
the furnaces under these varying rates of combustion. 

Q. What is a chimney ? 

A. It is the machine or opening through which 
the air and smoke from the furnace pass. 

Q. Is there any certain rule laid down for the 
height of chimneys ? 

A. No, as much depends on the position; if a 
stack or chimney is surrounded by hills or high 
buildings, it ought to be higher than those in more 
exposed places. 

Q. Is it necessary to have higher chimneys for 
long boilers than for short ones ? 

A. Yes ; chimneys should be higher for long boil- 
ers than for short ones, but it often happens thai 
short chimneys draw better than long ones. 

Q. Does it make any difference whether the inside 
of the chimney is round or square ? 

A. Yes ; as round chimneys have invariably more 
draft than square ones. 

Q. Does it make any difference whether the open- 



NON-CONDENSING STEAM-ENGINES. 87 

ing in a chimney is more or less than the area of the 
flues or tubes ? 

A. Yes ; the opening in the chimney ought to be 
in all cases one-fifth greater than the combined areas 
of the flues or tubes ; if it is less, it will destroy the 
draught. 

Q. Should the opening in the chimney be wider 
at the bottom than at the top ? 

A. No ; it should be just the reverse : it should be 
wider at the top than at the bottom ; if it is not, it 
will retard the draught. 

SMOKE. 

When coal is burned in an open furnace the prin- 
cipal products of combustion are carbonic acid and 
water ; certain portions of carbon escape combustion 
and constitute what is commonly called smoke, which 
is about 25 per cent, of the fuel in the shape of 
unconsumed gases and vapors. 

Various methods have been resorted to in this 
country and England for the purpose of burning 
smoke, but with only partial success. 

Q. Will you explain some of the different arrange- 
ments brought forward at different times for the pur- 
pose of burning smoke ? 

A. James Watt used a hopper to feed the coal into 
the furnace, supposing that the small quantity of gas 
or smoke evolved by that process would be readily 
consumed, but the plan soon fell into disuse. 



88 CATECHISM OF HIGH PRESSURE, OR 

Another device was to place a small furnace be- 
hind the bridge wall of the boiler, so that the smoke 
and gases passing over it might be ignited and con- 
sumed, but this was soon abandoned. Another 
method was to supply coal to one side of the furnace 
at a time, in the hope that the gas and smoke from 
the fresh coal would pass over the clean fire on the 
other side and be consumed ; but the carrying out of 
this plan involved great difficulties, and had to be 
abandoned. Another attempt to burn smoke was by 
introducing air into the furnace above the fire, through 
small holes in the door ; but the attempt was attended 
with no better success than the former, as the quantity 
of air admitted was in most cases greater than the 
quantity required, and had a tendency to chill the 
gases, and the result was the air and smoke passed 
into the chimney without becoming ignited. 

Another, and one of the latest attempts to burn smoke, 
is to introduce a portable or movable tube into every 
tube of the steam-boiler, for the purpose of separating 
the gas and smoke into thin sheets, in hopes the gas 
or smoke would become ignited. But the plan was im- 
practicable, as it involved great trouble and expense. 

Q. Do you believe that smoke can be successfully 
burned in common furnaces ? 

A. Not until the conditions under which it might 
be burned are more practically defined. First, the 
quantity of air that passes through the furnace more 
fully understood ; secon3, the temperature of the 



N0N- CONDENSING STEAM-ENGINES. 89 

furnace itself better known ; third, the quantity of 
air required to burn different kinds of fuel,— three 
conditions that are very imperfectly understood by 
theorists, experts, and engineers at the present day. 

GRATE-BARS. 

Perfect combustion is the starting-point in the 
generation of steam ; the conversion of coal and air 
into heat must be the first process, and the second is 
to apply that heat with full effect to the boiler. The 
oxygen of the air is the only supporter of combus- 
tion, and the rate of combustion produced and the 
amount of heat generated in the furnace depend on 
the quantity of air supplied, and the quantity of air 
admitted depends on the size of the opening through 
which it passes. Then, as a matter of course, the 
grate-bars that offer the least obstruction to the air 
passing through them, and afford the largest area 
for the air combined with an equal distribution of 
the same, must be the most perfect for the purposes 
of combustion. 

Grate-bars to be efficient must have a narrow sur- 
face exposed to the fire, and the spaces for admitting 
air must be numerous and well distributed to pro- 
duce perfect combustion of the fuel. 

IMPROVED GRATE-BARS AND BEARER. 
The accompanying cut represents Kearney's 
Grate-bars and Bearer, which, it is claimed, are 
8* 



90 CATECHISM OF HIGH PRESSURE, OR 




NON-CONDENSING STEAM-ENGINES. 91 

not only of unusual durability, but also offer the 
advantage of a considerable saving in fuel. Fig. 1 
shows a perspective view of the bars, of which a 
suitable number are joined together to form conve- 
nient-sized sections. 

A is a longitudinal brace, to which are attached 
the transverse bridges, B B, of one of which an end 
view is shown in Fig. 2. The same illustration repre- 
sents an end section of the bars, and the manner in 
which the latter are connected by the transverse 
blocks, C. It also will be noticed that the interstices 
or slots between the bars are widest at the bottom. 
The upper surface of the grate is corrugated, the ob- 
ject being to give an equal amount of metal at every 
point, and thus obviate the warping due to unequal 
contraction and expansion. There is also another 
and important advantage gained by this mode of 
construction. On the perfectly flat surface which 
would be afforded were the bars even on top, a 
thick layer of coal would easily pack, and, forming 
clinker, would make an air-tight covering, and thus 
effectually hinder the draught. This difficulty is 
entirely avoided by the corrugations, which admit of 
a free circulation of air under the fuel, from the fact 
that there will always be portions of the bars — gen- 
erally the lowest points of the curves — on which the 
coal will not directly rest, so that open sjDaces will be 
formed, through w r hich air can pass. Moreover, the 
irregular surface serves as a guide to the fireman to 
inform him, in cleaning the fire, when his slice-bar 



92 CATECHISM OF HIGH PRESSURE, OR 

has reached the grate. The shape of the interstices 
between the bars, to which attention was directed 
above, is favorable to the ready passage of the ashes, 
while it aids in preventing clogging by clinker or 
otherwise. 

The ends of the bars are open and bevelled as 
shown, the points of the extremities of two contiguous 
sections meeting on the upper surface of the bearer. 
This construction, as will be more clearly appre- 
hended when considered in connection with the form 
of the bearer, by affording open ends, admits of a free 
circulation, and also prevents the bars from warping, 
and thus becoming useless before they are half worn 
out. 

Fig. 3 represents a side view of a bearer on which 
the sections of grate rest. Figs. 4 and 5 are respec- 
tively longitudinal and vertical sections of the same. 
The bearer consists of two parallel bars pierced with 
a number of circular openings and connected together 
by transverse pieces, D D. The appliance is, there- 
fore, in fact, a frame which, from the small amount 
of metal it contains, opposes but slight resistance to 
the passage of the draught. It is evident that a promi- 
nent merit of this invention is the ingenious combina- 
tion of the hollow bearer and open ends of the sections 
of bars, so that the part of the grate which, in ordi- 
nary use, is the most liable to become packed and 
difficult to keep clean, is here as free and as clear as 
any other portion. A uniform circulation of air is 
consequently afforded through the entire length of 



NON-CONDENSING STEAM-ENGINES. 93 

the grate, and also a transverse current through the 
open supports on the under side. J 

This device has been thoroughly tested for some 
time, during which a continuous fire has been main- 
tained. The result of two years' experiment at the 
Jersey City waterworks, at Belleville, N. J., showed 
a direct saving of ten to fifteen per cent, in cost of 
both fuel and grates. 

Any information concerning these bars can be 
had from William Kearney, Belleville, N. J., or 
McFarland & McIlravy, Newark, N. J. 

DUTIES OP AN ENGINEER IN THE CARE AND 
MANAGEMENT OF THE STEAM-BOILER. 

Q. What is the first duty of an engineer when he 
takes charge of an engine and boiler ? 

A. It is his duty to examine his boiler and see that 
the water is at the proper level. 

Q. How much water should the boiler contain 
when in use ? 

A. The water should be kept up to the second 
gauge whilst working, and up to the third at night. 

Q. Why should the level of the water be raised at 
night ? 

A . As a precaution against the water becoming too 
low from leakage or evaporation. 

Q. In case the water should become dangerously 
low, what would be the duty of the engineer ? 



M CATECHISM OF HIGH PRESSURE, OR 

A. He should immediately draw the fire and allow 
the boiler to cool, and not admit any cold water to 
the boiler or attempt to raise the safety-valve, as it 
would be positively dangerous. 

Q. Why would it be dangerous to raise the safety- 
valve ? 

A. Because it would lessen the pressure in allow- 
ing the steam to escape from the boiler, thus per- 
mitting the water to rise up and come in contact 
with the overheated iron, and probably cause an 
explosion. 

Q. In case the water supply should be cut off 
from the boiler for a short time, what would be the 
duty of the engineer ? 

A. He should cover his fire with fresh fuel, stop 
his engine, and keep the regular quantity of water 
in the boiler until the accident is repaired and the 
water supply renewed. 

Q. How should an engineer proceed to get up 
steam ? 

A. He should first see that the water is at the 
proper level ; he should then remove all ashes and 
cinders from the furnace, and cover the grate with 
a thin layer of coal ; and after placing his wood and 
shavings on the coal, he will be ready to start his fire. 

Q. What advantage is it to place a covering of 
coal on the grate before the wood or shavings ? 

A. It is a saving of fuel, as the heat that would 
be transmitted to the bars is absorbed by the coal, 



NON-CONDENSING STEAM-ENGINES. 95 

and the bars are also protected from the extreme 
heat of the fresh fire. 

Q. Should an engineer allow his fire to burn grad- 
ually when he commences to get up steam from cold 
water ? 

A. Yes; as by allowing the fuel to burn very 
rapidly, some parts of the boiler become expanded 
to their utmost limits, whilst other parts are nearly 
cold. Of course, a great deal depends upon the time 
in which he has to raise his steam. 

Q, How should an engineer regulate his fire ? 

A. He should always keep the fire at a uniform 
thickness, and not allow any bare places or accumu- 
lations of ashes or dead coals in the corners of the 
furnace, as these places admit great quantities of cold 
air into the furnace and render the combustion very 
imperfect. 

Q. Should an engineer avoid excessive firing as 
much as possible ? 

A. Yes; as excessive firing is always attended 
with more or less danger, because the intense heat 
repels the water from the surface of the iron and 
allows the boiler to be burned. 

Q. How thick should an engineer keep his fires ? 

A. About 3 inches for anthracite coal and about 
5 inches for soft coal; but he should regulate the 
thickness of the fire according to the capacity of 
the boiler ; if the boiler is too small for the engine, 
the fire should be kept thin, the coal supplied in 



96 CATECHISM OF HIGH PRESSURE, OR 

small quantities and distributed evenly over the 
grate, and the grate kept as free as possible from 
ashes and cinders ; but if the boiler is extra large 
for the engine, the thickness^ of the fire makes but 
little difference. 

Q. What should an engineer do in case, from 
neglect or any other cause, his fire should become 
very low ? 

A. He should neither poke nor disturb it, as that 
would have a tendency to put it entirely out, but he 
should place shavings, sawdust, wood, or greasy 
waste, on the bare places, with a thin covering of 
coal ; then by opening the draught to its full extent, 
the fire will soon come up. If it should become 
necessary to burn wood on a cold fire, it is always 
best to make an opening through the coal to the 
grate-bars, so that the air from the bottom of the 
furnace can act directly on the wood and increase 
the combustion. 

Q. Should an engineer give great attention to the 
regulation of the draught in the furnace ? 

A. Yes ; the regulation of draught is one of the 
most important of an engineer's duties, for in fact it 
is next in importance to the regulation of the water 
in the boiler. 

Q. How do you explain that ? 

A. Because it is well known that immense quan- 
tities of fuel are recklessly wasted by ignorance and 
carelessness in the management of the draught. 



NON- CONDENSING STEAM-ENGINES. 97 

Q. How should an engineer regulate his draught 
to obtain the best results from the fuel ? 

A. He should have no more draught at any time 
than would produce a sufficient combustion of the 
fuel to keep the steam at the working pressure, as 
by opening the damper to its utmost limits great 
quantities of heat are carried into the chimney and 
lost. 

Q. Can an engineer carry out this principle of 
regulating the draught in all cases ? 

A. No ; only in furnaces and boilers that are suf- 
ficiently Targe to furnish the necessary amount of 
steam without forcing. Of course, where the boiler 
is too small for the engine, or has not sufficient heat- 
ing surface, it is impossible to economize fuel. 

Q. Do you consider it a good practice to throw a 
jet of steam under the furnace bars ? 

A. Only in some cases, where the draught is in- 
sufficient to produce the necessary combustion of the 
fuel ; but it is considered an advantage, before clean- 
ing the fire, to throw some water under the grate 
bars, as the oxygen from the steam thus generated 
under the furnace will unite with the oxygen of the 
atmosphere and insure a more rapid combustion of 
the fuel after the fire is cleaned. 

Q. Is it objectionable to throw steam or water 
under the grate-bars of locomotive boilers, when 
such boilers are used for stationary engines ? 

A. Yes ; as steam or water in the ash-pit forms a 
9 G 



98 CATECHISM OF HIGH PRESSURE, OR 

lye with the ashes and corrodes the iron and destroys 
the water-legs of the boiler. 

Q. Should an engineer in all cases keep his ash- 
pit clean ? 

A. Yes ; by allowing the ash-pit to become filled 
with ashes and cinders the air becomes heated to a 
high temperature before entering the fire, which ma- 
terially interferes with the combustion of the fuel ; 
the grate-bars also become overheated, and in many 
cases either badly warped or melted down. 

Q. How should an engineer keep his safety-valve ? 

A. He should keep it at all times in goocl working 
order, and move it at least once a day, particularly 
in the morning. 

Q. Why should he move the safety-valve every 
morning? 

A. To see that all its parts are in good working 
order before getting up steam. 

Q. Would you consider it reprehensible conduct 
on the part of an engineer who would weight his 
safety-valve in order to carry a pressure greater than 
that he knew to be safe? 

A. Yes ; such conduct, if proved, ought to be suf- 
ficient to disqualify any engineer from ever taking 
charge of an engine and boiler again. 

Q. What is the duty of an engineer in regard to 
blowing out his boilers ? 

A. He should carefully remove all the fire from 
the furnace, and see that the steam is at the proper 



NON-CONDENSING STEAM-ENGINES. 99 

pressure, say from 45 to 50 pounds. He should also 
close his damper. 

Q. Should any time intervene between the draw- 
ing of the fire and the blowing out of the boiler ? 

A. Yes ; at least one hour. 

Q. Why should the blowing out of the boiler be 
deferred for an hour after the fire is drawn ? 

A, To allow the furnace to cool, and prevent the 
boiler from being injured with the heat after the 
water is all blown out. 

Q. Why not blow out the boiler under a high 
pressure of steam, say 70, 80, or even 90 pounds to 
the square inch ? 

A. Because the higher the steam - pressure the 
higher the temperature of the iron, so that by blow- 
ing out the boiler under a high steam-pressure, the 
change is so sudden that it has a tendency to contract 
the iron and cause the boiler to leak. 

Q. Should the engineer fill his boiler with cold 
water immediately after blowing out ? 

A. No ; as the introduction of cold water into the 
boiler before the temperature of the iron becomes 
lower would in all probability cause the boiler to 
leak. 

Q. How often should an engineer blow out his 
boiler ? 

A. Whenever he discovers any appearance of 
mud in the water. 

Q. Is it not customary with some engineers and 



100 CATECHISM OF HIGH PRESSURE, OR 

owners of steam-boilers to blow out their boilers once 
a week ? 

A. Yes ; but the wisdom of this practice is ex- 
tremely doubtful, for, when fresh water is boiled, it is 
supposed to deposit its minerals, and after that it is 
not advisable to blow out the pure water and fill the 
boiler with water holding matter in solution and sus- 
pension ; once in two or three weeks is as often as 
boilers ought to be blown out. 

Q. Should an engineer, when filling his boilers, 
open some cock or valve in the steam-room of the 
boiler and allQW the air to escape ? 

A. Yes ; otherwise the air would retard the ingress 
of the water, and also collect in the steam-room of the 
boiler and prevent the regular expansion of the iron 
when the fire is started. 

Q. What do you mean by the steam-room of a 
boiler ? 

A. I mean that portion of the boiler occupied by 
steam above the water. 

Q. What is meant by the water-room in a steam- 
boiler ? 

A. That portion of the boiler occupied by water. 

Q. What do you call the fire-line of the boiler ? 

A. The fire-line of the boiler is a longitudinal 
line above which the fire cannot rise on account of 
the masonry by which the boiler is surrounded. 

Q. How often should an engineer clean the tubes 
or flues of his boiler ? 



NON-CONDENSING STEAM-ENGINES. 101 

A. At least once a week ; he should also remove 
all ashes and soot that become attached to the out- 
side of the boiler. 

Q. What advantage is gained by cleaning the 
flues and tubes regularly, and also removing the soot 
and ashes that become attached to the boiler ? 

A. It makes a great saving in fuel, as it allows 
the fire to act directly upon the iron. 

Q. How often should an engineer clean his boilers ? 

A. Every three months, if possible. 

Q. Should an engineer, when cleaning his boilers, 
examine all stays, braces, seams, and angles of the 
boiler or boilers ? 

A. Yes ; he should make a thorough examination 
of all parts of the boiler, seams, rivets, crown-sheet, 
crown-bars, crow-feet, cotters and braces ; he should 
also sound the shell of the boiler with a very light 
steel hammer. 

Q. Why should the engineer sound the boiler ? 

A. Because it is the only way in which he can 
determine the condition of the iron. 

Q. How often should an engineer test his steam- or 
pressure-gauge ? 

A. At least once a year. 

Q. Can an engineer test a steam-gauge himself? 

A. No ; unless he has a test-gauge, which is not 
very often the case. The gauge ought to be tested 
by another gauge built or made expressly for that 
purpose. 
9* 



102 CATECHISM OF HIGH PRESSURE, OR 

Q. How should an engineer keep his glass water- 
gauges ? 

A. He should keep them perfectly clean inside 
and out. 

Q. How can an engineer clean his glass water- 
gauges inside ? 

A. By opening the drip-cock and closing the water- 
valve, and allowing the steam to rush down the glass 
and carry out the mud or sediment. They should also 
be swabbed out with a piece of cloth or waste on a 
small stick, when the boiler is cold ; but care should 
be taken not to touch the inside of the glass with Yvdre 
or iron, as an abrasion will immediately take place. 

Q. In case an engineer has a glass water-gauge, 
should he neglect his gauge-cocks ? 

A. No ; he should examine them several times in 
the day, see that they are in good working order, and 
grind or repair them if necessary. He should always 
be sure to shut them tight, as by leaving them loose 
the steam and water destroy the seat of the valve and 
render them useless. 

Q. What evidence do dirty or broken glass gauges, 
filthy boiler-heads, leaking and muddy gauge-cocks 
give of a man's ability as an engineer ? 

A. They furnish strong evidence of his ignorance 
or neglect of duty. 

Q. What should an engineer do in cold weather, 
when his pumps, boiler connections, steam-gauges, or 
water-pipes are liable to be frozen ? 



NON-CONDENSING STEAM-ENGINES! 103 

A. He should open all drip- or discharge-cocks and 
allow the water to run out when he stops work at 
night, and in the morning make a thorough exami- 
nation of all steam and water connections before he 
starts his fires. 

Q. In case it becomes necessary to stop the engine, 
and the steam commences to blow off at the safety- 
valve, what is the duty of the engineer ? 

A. He should immediately start his pump or in- 
jector, and also cover his fire with fresh coal, so that 
the circulation might be kept up by the feed-water, 
and the extreme heat of the fire absorbed by the 
fresh coal, instead of being communicated to the iron 
of the boiler ; and he should not attempt, under any 
circumstances, to interfere with the free escape of the 
steam through the safety-valve. 

Q. Whenever the fire-door of the furnace is open, 
should the damper be closed, if possible ? 

A. Yes ; the door and the damper should never be 
open at the same time, unless it is absolutely neces- 
sary, as the cold air, that would otherwise have to 
pass through the fire and become rarefied, rushes in 
through the open door above the fire and impinges 
on the tube and crown-sheets, and has a tendency to 
contract the seams and cause them to leak. 

Q. In case it should become necessary to examine 
the check-valve while steam is on the boiler, how 
should it be done ? 

A. The stop-cock between the check-valve and 



104 CATECHISM OF HIGH PRESSURE, OR 

boiler should be first closed before any attempt is made 
to unscrew or remove the check. Any neglect to close 
the stop-cock might result in a serious accident. 

Q. How should an engineer proceed to make a 
joint on the man-hole or hand-holes of his boiler? 

A. He should first carefully remove all gum or 
other material from the seat or flange where the joint 
is to be made, so that the gasket may have a smooth 
and solid bearing before he commences to tighten 
the nut. 

Q. Do you know any other important duty an en- 
gineer should consider himself bound to perform ? 

A. Yes ; he should daily make a thorough exami- 
nation of all safety-valves, pumps, injectors, and all 
steam and water connections. 

Q. What should be said of an engineer that would 
allow his boiler and engine to run on from bad to 
worse, expecting some day to have a general overhaul- 
ing, instead of making repairs as they were needed ? 

A. He should be considered totally unfit for the 
position of an engineer. 

Q. When can it be said that an engineer has done 
his duty ? 

A. When he shows by his work that he has cared 
for everything connected with his engine and boiler 
in the best possible manner. 



NON-CONDENSING STEAM-ENGINES. 105 




100 HOR8B-P0WER VERTICLE STEAM-ENGINE. 

Kelly, Howell & Ludwig, Philadelphia, Pa. 



106 CATECHISM OF HIGH PRESSURE, OR 



m 



HIGH-PRESSURE STEAM-ENGINES. 

Before the introduction of the steam-engine, 
horses were used to furnish power for various kinds 
of work, such as pumping water out of mines, raising 
coal, etc. When it was proposed to substitute the 
power of steam for that of horses, the proposal natu- 
rally took the form of furnishing a steam-engine ca- 
pable of doing the work of a number of horses. 
Hence followed the usage of stating the number of 
horses which any particular engine was equal to. 

Q. How is the power of a steam-engine generally 
expressed ? 

A. In horse-power. 

Q. What is a nominal horse-power ? 

A. 33,000 pounds raised 1 foot high in 1 minute. 

Q, Why is it that 33,000 pounds raised 1 foot 
iigh in 1 minute is adopted as a standard for a steam- 
£ ngine ? 

, A. Because, before the introduction of the steam- 
engine, it was found by experiment that with the 
average of horses the best speed for work was at the 
rate of 2} miles per hour; and at that rate of speed a 
horse could raise perpendicularly a weight of 150 



NON-CONDENSING STEAM-ENGINES. 107 

pounds 220 feet high in 1 minute, which is equiva- 
lent to 33,000 pounds raised 1 foot high in 1 minute, 
and was taken by Watt as a standard for horse- 
power, and is universally received as such. For in- 
stance ; an engine of 60 horse - power can raise 
33,000 pounds 1 foot high in a second, or an engine 
of 420 horse-power would raise 33,000 pounds 1 foot 
high in ^ of a second. 

Q. What is the indicated horse-power of an en- 
gine? 

A. It is the power of an engine as shown by an 
instrument called an indicator. 

Q. What is the actual horse-power of an engine ? 

A. It is the actual performance of the engine or 
the amount of power given out. 

Q. What is the net horse-power of an engine ? 

A. It is the available power of an engine as deter- 
mined by the indicator after deducting from it the 
power required to overcome the friction of the engine 
itself. 

Q. What should be considered the unit of com- 
mercial horse-power in high-pressure steam-engines ? 

A. 4 circular inches area of piston, with an aver-/ 
age pressure of 40 pounds to the square inch andTa 
piston velocity of 400 feet per minute. 

Q. What is the most convenient rule for finding 
the horse-power of an engine ? 

A. Multiply the area of the piston by the average 
pressure in pounds, less 5 pounds per square inch for 



108 CATECHISM OF HIGH PRESSURE, OR 

friction ; then multiply that product by the number 
of feet the piston travels per minute ; then divide by 
33,000 pounds. That will give the horse-power of 
the engine. 

For example : 

Diameter of cylinder in inches 10 

10 

Square of diameter of cylinder 100 

.7854 

Area of piston 78.54 

Pressure 60 lbs., cut-off J stroke ) , - 

Average press. 50 lbs., 5 off for friction 5 

39270 
31416 

3534.30 
250 

33000)883575.00 

26. horse -power. 

Another Rule for finding the ITorse-potver of an 
Engine. 

Multiply area of piston by boiler pressure, and this 
product by travel of piston in feet per minute ; di- 
vide this last product by 33,000 ; then deduct 13 per 
cent, for loss by friction and condensation. 



NOX-CONDEXSIXG STEAM-ENGINES. 109 

For example : 

Diameter of cylinder in inches 12 

12 

Square of diameter of cylinder 144 

.7854 

Area of piston 113.0976 

Pressure 60 

6785.856 
Travel of piston 300 

33000)2035756.800 

61.689 
Percentage off for friction, etc .13 

8.01957 
Horse-power of engine 53.669 

Q. What do you mean by " average pressure " ? 

A. I mean, if the pressure is 60 pounds per square 
inch, and cut off in the cylinder at i stroke, the aver- 
age pressure for the whole length of the stroke would 
be 50 pounds ; if cut off at f stroke, it would be 57 
pounds.* 

Q. How do you find the area of the piston ? 

A. Square the diameter of the cylinder, and mul- 
tiply the product by the decimal .7854. 

Q. Why do you square the diameter of the cylin- 
der and multiply by .7854 ? 

A. Because, when we square the diameter of the 

* See Table of Averages, page 116. 
10 



110 CATECHISM OF HIGH PRESSURE, OR 

cylinder, we get square inches, and when we multiply 
by .7854, we get the circular inches. 

Q. What is the meaning of the word " area " ? 

A. It is the amount of surface exposed to the action 
of the steam . 

Q. How do you find the travel of the piston in feet 
per minute? 

A. We first find the length of the stroke of the en- 
gine, and the travel of the piston is double the stroke. 

Q. What is the stroke of an engine ? 

A. Double the distance between the centre of the 
crank-pin and the centre of the crank-shaft. For in- 
stance, if it is 12 inches between the centre of the 
crank-pin and the centre of the crank-shaft, the en- 
gine is 2 feet stroke. 

Q. Is the stroke and a revolution of an engine just 
the same ? 

A. Yes ; whether we call it a stroke or a revolu- 
tion, the travel of the piston is the same. 

Q. What do you mean by the effective pressure on 
the piston ? 

A. I mean that the piston is under the action of 
the pressure of the steam from the boiler on one side, 
and the back-action caused by the pressure of the at- 
mosphere on the other side. The difference between 
the two pressures is the effective pressure on the pis- 
ton, and the power developed will depend upon the 
number of square inches acted upon, and the speed 
of the piston in feet per minute. 



NON-CONDENSING STEAM-ENGINES. Ill 

Q, What ought to be the minimum speed of the 
piston of any engine ? 

A. 240 feet a minute. 

Q. Is the pressure in the boiler and the pressure 
in the cylinder nearly equal in all cases ? 

A. No ; the pressure in the cylinder is in many 
cases 3 less than the pressure in the boiler ; for that 
reason, in calculating the power of whole-stroke en- 
gines, or engines that do not work by expansion, not 
more than f of the boiler pressure should be taken 
as the effective pressure in the cylinder. 

Q. From what cause does the difference between 
the pressure in the boiler and the pressure in the 
cylinder arise ? 

A. It arises from different causes; first, from a 
nial construction of the steam-pipe and steam-ports ; 
second, from loss by radiation and condensation ; 
third, by the action of the governor ; and fourth, by 
the bad condition of the piston. 

Q. What is the most economical steam pressure to 
use in the cylinder of a high-pressure engine ? 

A. From 80 to 90 pounds to the square inch. 

Q. Why should 80 or 90 pounds to the square 
inch be more economical than lower pressure, say, 
40 or 45 pounds to the square inch ? 

A. Because the loss is greater in low pressure than 
it is in high, owing to the pressure of the atmosphere ; 
for instance, if we have a pressure of 45 pounds to 
the square inch on the piston, the loss by atmospheric 



112 CATECHISM OF HIGH PRESSURE, OR 

pressure is 15 pounds to the square inch, which is 
about ^ of the pressure on the piston, leaving only 
30 pounds for useful effect and to overcome the fric- 
tion of the engine ; if we have a pressure of 90 pounds 
to the square inch, the loss is only 15 pounds to the 
square inch, or about |. 

Q. Has the above calculation any reference to 
the pressure on the boiler as indicated by the gauge ? 

A. No ; it refers only to the pressure on the piston. 

Q. Does it take any more fuel to carry steam at a 
pressure of 90 pounds to the square inch than it 
does at 50 pounds to the square inch ? 

A. No ; not quite so much. 

Q. If that is the case, why not carry a pressure of 
100 pounds to the square inch, or more ? 

A. Because, to carry such high pressures, it would 
be necessary to have boilers of smaller diameters and 
of better material ; they should also be carefully pro- 
tected from radiation by good non-conductors. 

Q. Does a steam-engine that is too large for the 
work to be done, and running at a high speed, waste 
fuel? 

A. Yes ; as, for instance, an engine of 40 horse- 
power doing the work of a 20 horse-power engine, 
and running at a high speed, the steam would have 
to be throttled down, say, from 60 pounds boiler 
pressure to 25 pounds on the piston, which would be 
a loss of nearly f in fuel. 

Q. Is it a common error to get an engine too large 
for the power required ? 



NON-CONDENSING STEAM-ENGINES. 113 

A. Yes ; as the steam necessary to drive a 30 horse- 
power high-pressure engine with no load, would give 
more than 10 horse-power in a small engine. The 
cylinder of any engine should be of sufficient size to 
give the full power required, leaving a reasonable 
margin for variation in pressure, and for recuperative 
power under sudden increase of load, and no larger. 

Q. Are large engines doing the work easily, and 
working at a low pressure, economical ? 

A. Only when the number of revolutions is re- 
duced in proportion to the work to be done. 

Q. Is it difficult to fix the proper size of an engine, 
unless we know the power needed ? 

A. Yes ; it is almost impossible to fix the size of 
an engine, unless we know the number of machines 
to be run, and the power required to run them or 
any of them : for instance, if we wish to run 3 ma- 
chines, and it requires 10 horse-power for each ma- 
chine, the engine ought to be 34 horse-power ; if we 
wish to run 10 machines, requiring 10 horse-power 
each, the engine ought to be 115 horse-power. 

Q. Is it necessary to know the pressure that will 
be used, and also the speed at which the engine will 
be run, before we can fix the power of an engine ? 

A. Yes ; until we know the pressure to be carried, 
and the velocity at which the piston will travel, 
nothing very definite can be said as to the power of 
the engine. 

10* H 



V 

114 CATECHISM OF HIGH PRESSURE, OR 

Q. Which would be the most practicable way of 
increasing the power of an engine ? 

A. First, by increasing the pressure in the boiler ; 
second, by increasing the speed of the engine ; third, 
by putting on a new cylinder, which should not in 
any case be more than 2 inches in diameter larger 
than the old one. 

Q. "What ought to be the maximum piston speed 
of non-condensing engines ? 

A. Although there is a limit to the velocity of 
piston speed for all engines, that speed must be de- 
termined by the size and construction of the engine, 
as it would not be safe to subject any engine to a 
higher pressure than that for which it was built, nor 
to run it at a higher speed than its moving surfaces 
woulc 1 bear. The velocity of piston speed must range 
between 240 and 700 feet per minute, according to 
the circumstances of the case. 

Q. What are the four conditions that influence the 
economy of a steam-engine ? 

A. First, pressure; second, expansion; third, 
speed ; fourth, size of cylinder. 

Q. What are the three practical conditions that 
insure the greatest economy of steam ? 

A. First, the highest pressure ; second, the greatest 
number of revolutions ; third, shortest point of cut- 
off. If these three conditions are favorable, the 
highest point of economy is obtained. 

Q. What is the common mode of applying the 
power of steam to the piston of the steam-engine ? 



NON-CONDENSING STEAM-ENGINES. 115 

A. One is to allow the steam to flow from the 
boiler to the cylinder during the whole length of the 
stroke; the other is to cutoff the steam from the 
boiler when the piston has travelled a certain dis- 
tance. 

Q. What is the object of this last arrangement, 
viz., the closing of the communication between the 
cylinder and the boiler? 

A. The great object of this arrangement is the 
saving of fuel. 

Q. Does this account for some engines using more 
fuel and steam than others ? 

A. Yes; the reason why some engines use more 
steam than others of the same capacity is because the 
steam is not cut off or expanded. 

Q. If the load on an engine will be such as to al- 
low the steam to be cut off at a short point in the 
cylinder, what will be the effect? 

A. The steam will be expanded to its full availa- 
ble limits, and a great saving will be made. 

Q. If steam be applied to the piston the full length 
of the stroke, what will be the average pressure in 
the cylinder ? 

A. The average pressure will be as the pressure 
per square inch upon the piston. 

Q. If steam, at 65 pounds to the square inch, be 
applied to the piston and cut-off at half-stroke, what 
will be the average pressure the whole length of the 
stroke ? 



116 



CATECHISM OF HIGH PRESSURE, OR 



A. 55 pounds to the square inch, being only 10 
pounds less than the full pressure, or 16 per cent, of 
loss in power, though half the quantity of steam was 
only used. This alone would effect a saving of 34 
per cent, of fuel. 

f TABLE. 

Showing the Average Pressure of the Steam upon the Piston 
throughout the Stroke, when cut off in the Cylinder from 
\ to f, commencing with 25 pounds and advancing in 5 
pounds up to 100 pounds Pressure. 



Steam Cut-off in the 
Cylinder. 



Pressure in pounds at the Commencement of the Stroke. 



25 30 35 40 45 50 55 60 



Average Pressure in pounds upon the Piston. 



15 


17| 


20| 23| 


26! 


29| 


32! 


21 


25i 


29* 33| 


38 


42^ 


46* 


24 


28| 


33* 38* 


43J 


48i 


53 



35f 



57f 



Pressure in pounds at the Commencement of the Stroke. 



Steam Cut-off in the 
Cylinder. 



65 70 75 80 85 90 95 100 



Average Pressure in pounds upon the Piston. 



i 


38| 


41! 


44! 


47! 


50! 


53! 


56! 


59! 


1 

2 


55 


59i 


63* 


67! 


72 


76i 


80* 


84! 


5. 

4 


62* 


67* 


72J 


77J 


82 


87 


91! 


96* 



Q. Which do you consider the most economical 
and available points at which to cut off steam in the 
cylinder ? 



NON-CONDENSING STEAM-ENGINES. 117 

A. I, i, and f of the stroke or travel of the piston. 
Beyond f , the saving is so small as to be hardly per- 
ceptible. 

Q. What are the conditions under which steam 
can be worked expansively with the best results ? 

A. Every part of the steam-pipe, cylinder, and 
connections through which the steam flows from the 
boiler to the cylinder, must be carefully covered with 
some good non-conducting protectors ; for, unless the 
temperature of the steam and the temperature of the 
cylinder are kept nearly uniform, most of the bene- 
fits to be gained by expansion will be lost by radia- 
tion through the steam-pipe and the cylinder on the 
outside, and by condensation on the inside. 

Q. Are the advantages arising from the working 
of steam expansively increased as we raise the pres- 
sure? 

A. Yes ; steam at a pressure of 70 pounds to the 
square inch, worked expansively, will perform more 
than 7 times the duty of steam at 25 pounds per 
square inch. 

Q. Is it necessary to make the cylinders larger in 
cases where steam is to be worked expansively ? 

A. No ; with high pressures, by w T hich expansion 
is most available, the cylinders of steam-engines can 
be smaller than they are usually made. 

Q. When steam is worked expansively, which is 
the most effectual method of cutting off? 

A. By the main valve. 



118 



CATECHISM OF HIGH PRESSURE, OR 



LAP ON THE SLIDE-VALVE. 




"C" C 

A A, Valve-seat. E E, Valve-face. F F, Steam-ports. G G, Bars. C, Ex- 
haust-port. Dotted lines, H H, indicate outside lap. Dotted lines, 1 1, in- 
side lap. J, Exhaust-cavity in valve. 

Q. What is " Lap " on the slide-valve ? 

A. It is the lengthening of the valve to cut off the 
steam at i stroke, or any other point desired ; for in- 
stance, when the valve is placed at i stroke over the 
port, the amount by which it overlaps each steam- 
port, either internally or externally, is known as lap. 
On the steam side it is named outside lap, on the ex- 
haust side, inside lap ; when the term lap and lead 
is used, it designates outside lap and lead. 

Q. What is meant by inside clearance ? 

A. When the valve is so formed that at } stroke 
the faces of the valve do not close the steam-ports 
internally, the amount by which each face comes 
short of the inner edges of the ports is known as 
inside clearance. 

Q. In what way is the distribution of the steam 
passing to and from the cylinder controlled ? 

A. By the outer and inner edges of the steam- 
ports and of the valve. 



NON-CONDENSING STEAM-ENGINES. 119 

Q. Does the width of the exhaust-port, or the thick- 
ness of the bridges (or bars), make any difference ? 

A. No, if the valve is rightly proportioned ; as 
the extreme edges of the steam-ports and those of 
the valve regulate the admission, and the inner edges 
of the ports and the valve control the exhaust, as 
before stated. 

Q. How many distinct changes occur in the cylin- 
der for every stroke of the piston ? 

A. Four : first, admission ; second, suppression ; 
third, release ; and, fourth, compression. 

Q. When does expansion of steam take place in 
the cylinder? 

A, It takes place during the interval between the 
closing of the steam -port and the release of the 
exhaust. 

Rule by which to ascertain the amount of lap neces- 
sary, on the steam side of a slide-valve, to cut the steam 
off at various fractional parts of the stroke. 

To cut the steam off after the piston has passed 

through 

i 7 2 3 5 7 ii 

2 T2 3 4 6 8 12 

of its stroke. Multiply the given stroke of the 
valve by 

.354 .323 .289 .250 .204 .177 .144, 
and the product is the lap of the valve in terms of 
the stroke. 



120 



CATECHISM OF HIGH PRESSURE, OR 



A TABLE ' 

Showing the amount of "Lap" required for Slide-valves 
when the Steam is to be worked expansively. 

The traverse of the valves being ascertained, and also the 
amount of cut-off desired, the following Table shows the 
amount of " lap " required : 



Traverse 
of the 

Valve in 
inches. 



TJie traverse of the piston where the steam is cut off. 



1 

3 


5 
72 


* 


7 
75 


2 
3 



£ 



The reqnired "lap." 



10 
T2 



2 

2} 

3 

31 

4 

4} 

5 

5} 

6 

6} 

7 

71 

8 

8} 

9 

9} 
10 
10} 

11 
11} 

12 






2 
9 i 

2^ 
2j 



Q 3 

^76 

3 r 6 g 
3* 

Ql S 

4 

4£ 

4 T 7 e 

4{| 



3 


1 1 


5 


9 


» 


7 


_ 4 


iff 


8 


76 


2 


75 


1 


7 
8 


1 3 

1 6 


1 1 

76 


9 
1 6 


1 

5 


It's 


M 


1 


15 

1 6 


3 

4 


5 

5 


1A 


1A 


H 


It's 


1 


7 
5 


1 9 
1-76 


1 *7 
1 T6 


1A 


1] 


Vs 


1 


1 ! 3 
J-76 


l- 9 - 
1 6 


M 


M 


M 


1* 


2 


113 


1A 


U 


J* 


u 


2 T % 


2 


113 

- 1 re 


1 5 

1 8 


1* 


11 


^] 6 


9 3 
Z T6 


2 


x 1 6 


M 


14 


^1 6 


9 ? 


2A 


2 


113 
A l 6 


if 


911 

^1 6 


9 9 

Z T6 


25 


*A 


2 


if 


3 


01 1 
Z 16 


2^ 


2* 


2A 


i* 


Q_3_ 
°1 6 


3 


2| 


2A 


2| 


2 


°] 6 


2 3 


2|| 


2ft 


2^ 


2| 


Q 5 


»A 


3 


m 


2| s 


2i 


qi 3 
6 T6~ 


8* 


Q 3 


3 


91 3 
^76 


21 


4 


3|S 


9 5 
°T6 


9 3 

°T6 


3 


2£ 


4i 


4 


3^ 


9 5 
°Tg 


d 8 


2| 


*A 


4-1 

^ 4 


3| 


3^ 


3 T 3 , 


2J 


4- 9 7T 

^l 6 


4- 7 - 


3g 


3g 


31 


9 7 

Z 8 


4.1 3 
^7 6 


4- 9 ^ 

^1 6 


4i 


4 


3| 


3 



7 
76" 

i 9 g 

3 
4 
1 3 

75 

7 

I s 
ll 

i 

M 
J* 

2 8 



8 



9 1 

2/ g 

2 5 
21 
2A 



N0N- CONDENSING STEAM-ENGINES. 



121 




The arrow at A indicates outside lead. The arrow at B indicates inside 
lead. P is the piston at the beginning- of the stroke. C C, clearance at 
end of the cylinder. 

"LEAD" ON THE SLIDE-VALVE. 

Q. What is " Lead " on the slide-valve ? 

A. It is the amount of opening the port has on the 
steam end when the engine is on the " dead centre." 

Q. What do you consider the proper amount of 
"lead"? 

A. The amount of " lead " on the valve must be 
determined by the circumstances of the case, as it is 
impossible to fix the exact amount for all engines ; 
in most cases from 3^ to T ^ of an inch is sufficient, 
but in some engines it is necessary to give i of an 
inch or even i lead. The amount of lead for any 
engine will depend on the speed, the work to be done, 
the points of cut-off, etc, 
11 



122 CATECHISM OF HIGH PRESSURE, OR 

Q. What is lead on the exhaust f 

A. It is the amount of opening the exhaust-port 
has when the piston is at the end of the stroke, or, in 
other words, when the crank is on the dead centre. 

Q. What do you consider the proper amount of 
lead on the exhaust? 

A, In good practice, the amount of lea % d on the ex- 
haust should be double the amount of lead on the 
steam-port. The exhaust in all cases ought to be 
liberated soon enough to preclude the possibility of 
back pressure, but exhaust-lead may be carried to 
excess. The proportioning of slide-valves presents 
so many complicated considerations, that it is impos- 
sible to give any definite instructions in any particu- 
lar case without a full knowledge of the circum- 
stances. 

Q. What would be the effect on the engine if the 
exhaust is liberated too soon ? 

A. It would materially diminish the power of the 
engine ; and if the engine was running at a slow speed 
under a heavy load, it might be difficult for the en- 
gine to complete the stroke, or, in other words, to 
pass its centres. The lead on the exhaust must be 
determined by the speed, the degree of expansion, 
and the amount of work to be done by the engine. 
For some classes of engines, such as pumping, propel- 
ling, or engines drawing heavy freight-trains up steep 
grades, steam must be forced into the cylinder to the 
last possible point of the stroke. Every engine should 



NON-CONDENSING STEAM-ENGINES. 123 

be specially arranged both for induction and educ- 
tion of steam, if the object is to get the full amount 
of power out of the engine. 

Q. How can' you determine accurately whether the 
exhaust opens at the right time or not ? 

A. Take off the " cap " or cover of the steam-chest, 
then disconnect the valve from the valve-rod ; now 
take a short straight-edge and place it lengthwise on 
the edge of the exhaust-port ; then with a sharp scribe 
lay off lines on the valve-seat, each side of the ex- 
haust-port, that will appear above the valve ; now lay 
the straight-edge on the valve-face and lay off simi- 
lar lines on the exhaust-chamber that will appear on 
the edges of the valve ; now place the valve on its 
seat, and give about %\ of an inch lead ; if the lines 
described on the valve-face are passed the correspond- 
ing lines on the valve-seat J g of an inch, the exhaust 
opens at the right time, if not, the exhaust-chamber 
in the valve ought to be cut away to give the neces- 
sary opening. 

" CUSHION." 

Q. What is "cushion"? 

A. " Cushion " is steam admitted to or retained in 
the cylinder in front of the piston to overcome the 
inertia caused by the reciprocating parts of the en- 
gine. When the piston is cushioned with live steam 
it is done by giving an extra amount of lead. In 
most engines the exhaust steam remaining in the. 



126 CATECHISM OF HIGH PRESSURE, OR 

Q. What is the stroke of the slide-valve ? 

A. It is the distance that the valve moves on its 
seat. 

Q. How do you find the stroke of the valve ? 

A. Move the valve in one direction to the extent 
of its stroke, and make a mark on the valve-rod ; 
then reverse the movement to the opposite extremity 
and also make a mark ; the distance between the two 
marks is the stroke or travel of the valve. 

Q. Can the travel of the valve be increased or 
lessened by means of an intermediate bearing or slot 
in the arm of the rocker t 

A, Yes; as the bearing in the rocker -arm that 
carries the eccentric hook is lengthened, we increase 
the stroke of the valve ; if the same bearing is short- 
ened, we lessen the stroke of the valve. 

Q. How do you find the throw of the eccentric ? 

A. Measure the eccentric at the point which is 
called the throw or the heaviest side ; now measure 
directly on the opposite or light side ; the difference 
between the two measures will be the throw of the 
eccentric. 

SIZE OF STEAM-PORT. 

Q. What proportion should there be between the 
area of the steam-ports of a steam-engine and the 
area of the piston ? 

A. Steam-ports are made, in good practice, from 



NON-CONDENSING STEAM-ENGINES. 127 



to jq the area of the piston; but they vary accord- 
ing to speed, etc. 



1 

76 



SIZE OF STEAM-PIPE. 

Q. What should be the diameter of the steam-pipe 
as compared with the diameter of the cylinder ? 

A. The diameter of the steam-pipe ought to be i 
the diameter of the cylinder, but it varies on large 
engines. If the area of the steam-pipe, as com- 
pared with the area of the cylinder, is too small, it 
will cause wire-drawing of the steam and " priming " 
in the cylinder ; 'for when the valve opens to admit 
steam to the cylinder, the rush of steam is so great 
that the water is carried over from the boiler to the 
cylinder, which is not only a great loss of power, 
but positively dangerous, as it occupies the clear- 
ance between the piston and the cylinder-head at 
the end of the stroke, and has a tendency to fracture 
the cylinder-heads. 

SIZE OF EXHAUST-PIPE. 

Q. What ought to be the diameter of the exhaust- 
pipe as compared with the diameter of the cylinder ? 

A. The diameter of the exhaust-pipe ought to be 
i the diameter of the cylinder. 

SIZE OF PISTON-EOD. 

Q. What ought to be the diameter of the piston- 
rod as compared with the diameter of the cylinder ? 



128 CATECHISM OF HIGH PRESSURE, OR 

A. The diameter of the piston-rod ought to be about 
\ the diameter of the cylinder, but when steel is used 
the diameter might be less. 



MATEKIAL FOR PARTS OF ENGINES. 

Q. What kind of material do you consider the 
most suitable and durable to use in the manufacture 
of steam-engines? 

A. For engines running at high speed, the piston- 
rod and crank-pin should invariably be made of 
steel ; the boxes should be of brass in the proportion 
of 7 of copper to 1 of tin, and 1 of " spelter " to every 
40 pounds of the mixture ; the iron for cylinders and 
guides, if made from pig-iron, should be melted about 
9 times, as that is the point at which cast-iron attains 
the most suitable density. 

Q. What do you consider the most suitable mate- 
rial for the gibbs or shoes on the cross-head ? 

A. Wood ; as hard brass or Babbitt metal has a 
tendency to wear the guides out of true, which incurs 
the expense of having them replaned on the face. 
Wood is free from the above objections, as it never 
wears or disfigures the guides ; atso it requires but 
little oil, and the cost is very trifling. Lignum vitce 
and apple-wood answer a very good purpose for gibbs, 
the latter is preferable, as it is so much easier to work. 
Glass is sometimes used, and is said to answer very 
well for that purpose. 



NON-CONDENSING STEAM-ENGINES. 129 

SPRING-PACKING. 

Q. Does the setting out of the packing-rings in 
cylinders require great care and judgment? 

A. Yes ; for, like the setting of valves of steam- 
engines, no uniform rule can be laid down for that 
kind of work. If the packing is set out too tight, it 
diminishes the power of the engine, and by the in- 
creased friction has a tendency to flute or destroy 
both the surface of the packing and the inside of the 
cylinder. If the packing is too slack, and leaks, the 
steam occupies the cylinder in front of the piston, 
producing excessive cushioning, and materially di- 
minishing the power of the engine. 

PROPORTIONS OF ENGINES. 

Q. What would you consider good proportions for 
steam-engines ? 

A. The diameter of cylinders of well-proportioned 
steam-engines ought to be about equal to the length 
of the crank between the centres ; a 6-inch cylinder 
12-inch stroke, 12-inch cylinder 24-inch stroke, 5-inch 
cylinder 10-inch stroke, 10-inch cylinder 20-inch 
stroke, as there is more vibration to long-stroke than 
to short-stroke engines. But the amount of work to 
be done and the speed of the piston must, to a certain 
extent, determine the diameter of the cylinder and 
the length of the stroke ; engines intended to be run 
at high speed must of necessity be of short stroke. 

I 



130 CATECHISM OF HIGH PRESSURE, OR 

Q. Are short-stroke engines more economical than 
long-stroke ? 

A. Yes ; in all cases where steam pressure points 
of cut-off and travel of piston are the same. 

REVERSING AN ENGINE. 

Q. How would you proceed to reverse an engine ? 

A. First, make a mark on the side of the eccen- 
tric near the shaft, with a scribe or small chisel ; 
make a corresponding mark on the shaft at the same 
point ; then place one point of a pair of callipers on 
the mark on the shaft, and with the other point find 
the centre of the shaft on the opposite side ; then with 
a scribe mark this point also ; now unscrew the eccen- 
tric, and move it around in the direction in which the 
engine is intended to run until the mark on the eccen- 
tric comes into line with the second mark on the shaft ; 
then make the eccentric fast, and the engine will run 
in the opposite direction. 

Q. Does it make any difference in what position 
the crank is when the eccentric is moved ? 

A. No. 

PUTTING AN ENGINE IN LINE. 

Q. How would you proceed to put an engine in 
line f 

A. First, remove the cylinder-heads, piston, cross- 
head and connecting-rod ; now attach a small piece 
of iron or wood to the back flange of the cylinder ; 



EON-CONDENSING STEAM-ENGINES. 131 

fasten a small line to that finger and connect this line 
with a piece of iron or wood fastened in the floor at the 
back end of the bed-plate ; now take a pair of inside 
callipers and find the distance between the line and 
the inside of the cylinder at four different points in 
the back and front ends of the cylinder ; move the 
line attached to the stake at the back end of the bed- 
plate until all the points at the front and back ends 
of the cylinder are equally distant from the line ; 
now move the crank up and see if the centre of the 
crank-pin *feels the line ; if so, move the crank on the 
other centre, and if the point at which the crank-pin 
strikes the line corresponds with the point on the other 
centre the engine is in line ; if not, either the cylinder 
or the pillow-blocks will have to be moved, as the 
case may be. 

Q. After the engine is "lined," how would you 
proceed to adjust the different parts? 

A. First, insert the piston in the cylinder and slip 
on the packing-box and cross-head ; now bring the 
centre of the piston -head to the centre of the 
cylinder by means of the set-screws or wedges, or 
whatever mechanical device may be used for that 
purpose ; then screw up the follower-bolts ; now lay 
a spirit-level on the piston-rod between the packing- 
box and cross-head. If the end of the rod next the 
cross-head is high, it can be low T ered by slacking up 
the set-screws in the jaws of the cross-head. If the 
end next the cylinder is high, it can be levelled 



132 CATECHISM OF HIGH PRESSURE, OR 

by screwing down the set-screws in the jaws; the 
piston-rod and cross-head should be levelled at both 
ends of the guides. Next place the box and strap 
on the wrist of the cross-head and put the connecting- 
rod in position and insert the key and gibb. Now 
move the crank to a convenient position and slip oil 
the box and strap on the crank-pin and insert the 
key and gibb. It often happens in driving the keys 
on engines that they are adjusted too tightly, causing 
them to heat and destroy the bearings. The driving 
of keys on engines, like the adjusting of packing- 
rings in cylinders and the setting of valves, requires 
the exercise of great care. 

SETTING UP ENGINES. 

Q. How would you proceed to set up an engine ? 

A. Before commencing to set up an engine, it will 
be necessary to determine 

First The position or location the engine is to 
occupy in the shop or factory. 

Second. The line of the main shafting in the build- 
ing, if there be any ; if not, the line of the building 
itself, at at least three different points in the direc- 
tion in which the main shafting is to run ; now line 
down from the centre of the main shaft, or from the 
line of the building, at two different points, to the 
floor on which the engine is to stand, and from these 
points line to the engine-shaft. 

Third. Determine the height the bed-plate is to 



NON-CONDENSING STEAM-ENGINES. 133 

stand above the floor ; also the depth of the founda- 
tion, which in most cases would be about 3 feet below 
the level of the floor and 18 inches above. 

Fourth. Make a tamplet the exact counterpart of 
the bed-plate, in which to hang the foundation-bolts ; 
now set this upon four props at right angles to the 
main shaft in the building. 

Fifth. Lay up the brick foundation to the level at 
which the engine is intended to stand ; then remove 
the tamplet, and lower the bed-plate on to the foun- 
dation. 

Sixth. Great care should be taken, w 7 hen screwing 
down the foundation-bolts, to have the bed-plate per- 
fectly level in every direction. 

Seventh. A line should now be drawn exactly 
through the centre of the cylinder, and another line 
through the centre of the pillow-blocks ; and if these 
two lines strike each other at right angles, the engine 
is properly set up. 

Eighth. A straight-edge should now be placed 
across the bottom of the main bearings, in order 
to determine, by means of a spirit-level, whether 
the pillow-block boxes are perfectly level. 

Ninth. The crank-shaft should now be placed in 
position and turned around several times, for the 
purpose of determining whether it bears equally in 
the boxes ; if it does, the fly-wheel and driving-pulley 
can then be placed in position on their shafts, and all 
the other parts of the engine adjusted. 
12 



134 



CATECHISM OF HIGH PRESSURE, OR 



TABLE, 

Containing the Circumferences and Areas of Circles from 4 
to 26 inches in Diameter 



Diam. 


Circumfer. 


Area. 


Diam. 


Circumfer. 


Area. 


4 in. 


12.5664 


^~5664 


1 3 
1 6 


18.2605 


26.5348 


i 

1 6 


12.7627 


12.9622 


7 
8" 


18.4569 


27.1085 


1 

8 


12.9591 


13.3640 


1 5 
76. 


18.6532 


27.6884 


3 
76 


13.1554 


13.7721 


6 in. 


18.8496 


28.2744 


1 
4 


13.3518 


14.1862 


i 

T6~ 


19.0459 


28.8665 


5 
76" 


13.5481 


14.6066 


8 


19.2423 


29.4647 


3 

8 


13.7445 


15.0331 


3 
T6 


19.4386 


30.0798 


7 
1 6 


13.9408 


15.4657 


1 
4 


19.6350 


30.6796 


1 


14.1372 


15.9043 


5 
1 6 


19.8313 


31.2964 


9 
76 


14.3335 


16.3492 


3 

8 


20.0277 


31.9192 


5 

8 


14.5299 


16.8001 


7 
T6" 


20.2240 


32.5481 


1 1 
1 6 


14.7262 


17.2573 


1 


20.4204 


33.1831 


3 

4 


14.9226 


17.7205 


9 
76 


20.6167 


33.8244 


1 3 

j Q 


15.1189 


18.1900 


5 

8 


20.8131 


34.4717 


7 
8 


15.3153 


18.6655 


1 1 
] 6 


21.0094 


35.1252 


1 5 


15.5716 


19.1472 


3 
4 


21.2058 


35.7847 


5 in. 


15.7080 


19.6350 


1 3 
1 6 


21.4021 


36.4505 


i 

76 


15.9043 


20.1290 


7 
8 


21.5985 


37.1224 


1 

8 


16.1007 


20.6290 


1 5 
I 6 


21.7948 


37.8005 


3 
76 


16.2970 


21.1252 


7 in. 


21.9912 


38.4846 


1 
4 


16.4934 


21.6475 


1 
I 6 


22.1875 


39.1749 


5 
7 6 


16.6897 


22.1661 


1 
8 


22.3839 


39.8713 


3 

8 


16.8861 


22.6907 


3 

76 


22.5802 


40.5469 


7 


17.0824 


23.2215 


1 
4 


22.7766 


41.2825 


1 

2 


17.2788 


23.7583 


5 
76" 


22.9729 


41.9974 


9 
76" 


17.4751 


24.3014 


3 

8" 


23.1693 


42.7184 


5 

8" 


17.6715 


24.8505 


7 
76" 


23.3656 


43.4455 


1 1 
76 


17.8678 


25.4058 


l 
5 


23.5620 


44.1787 


3 

4 


18.0642 


25.9672 


9 
1 6 


23.7583 


44.9181 



NON-CONDENSING STEAM-ENGINES. 



135 



TABLE.- (Continued.) 

Containing the Circumferences and Areas of Circles from 4 
to 26 inches in Diameter. 



Diam. 


Circumfer. 


Area. 


Diam. 


Circumfer. 


Area. 


5 

8 


23.9547 


45.6636 


7 
1 6 


29.6488 


69.9528 


1 1 
T6 


24.1510 


46.4153 


1 
•> 


29.8452 


70.8823 


3 
4 


24.3474 


47.1730 


9 
1 6 


30.0415 


71.8181 


1 3 
7 6 


24.5437 


47.9370 


5 

8 


30.2379 


72.7599 


7 
8 


24.7401 


48.7070 


1 1 
T6 


30.4342 


73.7079 


1 5 
1 ti 


24.9354 


49.4833 


3 

4 


30.6306 


74.6620 


8 in. 


25.1328 


50.2656 


1 3 
1 6 


30.8269 


75.6223 


i 

] 6 


25.3291 


51.0541 


7 
8 


31.0233 


76.5887 


1 

8 


25.5255 


51.8486 


1 5 
16 


31.2196 


77.5613 


3 

1Q 


25.7218 


52.8994 


10 in. 


31.4160 


78.5400 


4 


25.9182 


53.4562 


1 

8 


31.8087 


80.5157 


5 
1 6 


26.1145 


54.2748 


1 
4 


32.2014 


82.5160 


3 

8 


26.3109 


55.0885 


3 

8 


32.5941 


84.5409 


7 
1 6 


26.5072 


55.9138 


1 
2 


32.9868 


86.5903 


1 


26.7036 


56.7451 


5 

8 


33.3795 


88.6643 


9 
] 6 


26.8999 


57.5887 


3 

4 


33.7722 


90.7627 


5 

8 


27.0963 


58.4264 


7 
8 


34.1649 


92.8858 


1 1 
1 6 


27.2926 


59.7762 


11 in. 


34.5576 


95.0334 


3 

4 


27.4890 


60.1321 


i 

8 


34.9503 


97.2053 


1 3 

1 6 


27.6853 


60.9943 


1 

4 


35.3430 


99.4121 


7 
8 


27.8817 


61.8625 


3 


35.7357 


101.6234 


1 5 
T6 


28.0780 


62.7369 


1 

2 


36.1284 


103.8691 


9 in. 


28.2744 


63.6174 


5 

8 


36.5211 


106.1394 


i 

T6 


28.4707 


64.5041 


3 
4 


36.9138 


108.4342 


1 

8 


28.6671 


65.3968 


7 
8 


37.3065 


110.7536 


3 
7(> 


28.8634 


66.2957 


12 in. 


37.6992 


113.0976 


1 

4 


29.0598 


67.2007 


i 

8~ 


38.0919 


115.4660 


5 
] 6 


29.2561 


68.1120 


1 
4 


38.4846 


117.8590 


3 

s 


29.4525 


69.0293 


3 
8 


38.8773 


120.2766 



136 



CATECHISM OF HIGH PRESSURE, OR 



TABLE. —(Continued.) 

Containing the Circumferences and Areas of Circles from 4 
to 26 inches in Diameter, 



Diam. Circumfer. 



39.2700 
39.6627 
40.0554 
40.4481 
40.8408 
41.2338 
41.6262 
42.0189 
42.4116 
42.8043 
43.1970 
43.5857 
43.9824 
44.3751 
44.7676 
45.1605 
45.5532 
45.9459 
46.3386 
46.7313 
47.1240 
47.5167 
47.9094 
48.3021 
48.6948 
49.0875 
49.4802 
49.8729 
50.2656 
50.6583 



Area. 



122.7187 
125.1854 
127.6765 
130.1923 
132.7326 
135.2974 
137.8867 
140.5007 
143.1391 
145.8021 
148.4896 
151.2017 
153.9384 
156.6995 
159.4852 
162.2956 
165.1303 
167.9896 
170.8735 
173.7820 
176.7150 
179.6725 
182.6545 
185.6612 
188.6923 
191.7480 
194.8282 
197.9330 
201.0624 
204.2162 



Diam. Circumfer. 



X 
4 
3 

8 
1 

5 
8 
3 
4 

7 
8 

17 in. 

i 

8 
J. 
4 
3 

8 

i 

5 



4 

7 
8 

18 in. 
i 

8 
1 

4 
3 
8 
1 
2 
5 



19 in. 

i 

8 
1 

4 
3 

8 
1 

5 
8 
3 
4 

7 



Area. 



51.0510 
51.4437 
51.8364 
52.2291 
52.6218 
53.0145 
53.4072 
53.7999 
54.1926 
54.5853 
54.9780 
55.3707 
55.7634 
56.1561 
56.5488 
56.9415 
57.8342 
57.7269 
58.1196 
58.5123 
58.9056 
59.2977 
59.6904 
60.0831 
60.4758 
60.8685 
61.2612 
61.6539 
62.0466 
62.4393 



207.3946 
210.5976 
213.8251 
217.0772 
220.3537 
223.6549 
226.9806 
230.3308 
233.7055 
237.1049 
240.5287 
243.9771 
247.4500 
250.9475 
254.4696 
258.0161 
261.5872 
265.1829 
268.8031 
272.4479 
276.1171 
279.8110 
283.5294 
287.2723 
291.0397 
294.8312 
298.6483 
302.4894 
306.3550 
310.2452 



NON-CONDENSING STEAM-ENGINES. 



137 



TABLE. — (Continued.) 

Containing the Circumferences and Areas of Circles from 4 
to 26 inches in Diameter. 



Diam. Cireumfer. 



20 in. 
i 

8 
1 
4 
3 

8 
1 
2 
5 

8 
3 

4 
7 
8 

21 in. 
i 

8 
1 
4 
3 

8 

1 

$ 

5 
8 
3 
4 
7 
8 

22 in. 

i 

§■ 
i 

4 
3 

8 
1 

i> 
8 
3 
4 

7 
8 



62.8320 
63.2247 
63.6174 
64.0101 
64.4028 
64.7955 
65.1882 
65.5809 
65.7936 
66.3663 
66.7590 
67.1517 
67.5444 
67.9371 
68.3298 
68.7225 
69.1152 
69.5079 
69.9006 
70.2933 
70.6860 
71.0787 
71.4714 
71.8641 



Area. 



314.1600 

318.0992 

322.0630 

326.0514 

330.0643 

334.1018 

338.1637 

342.2503 

346.3614 

350.4970 

354.6571 

358.8419 

363.0511 

367.2849 

371.5432 

375.8261 

380.1336 1 

384.4655 

388.8220 

393.2031 

397.6087 

402.0388 

406.4935 

410.9728 



Diam. Circumfer. 



23 in. 



24 



m. 



S 

3 

4 

7 

2om. 
i 

8 
1 
4 
3 

8" 
1 
2 
5 
B" 
3 
4 
7. 
8 



72.2568 
72.6495 
73.0422 
73.4349 
73.8276 
74.2203 
74.6130 
75.0057 
75.3984 
75.7911 
76.1838 
76.5765 
76.9692 
77.3619 
77.7546 
78.1473 
78.5400 
78.9327 
79.3254 
79.7181 
80.1108 
80.5035 
80.8962 
81.2889 



415.4766 
420.0049 
424.5577 
429.1352 
433.7371 
438.3636 
443.0146 
447.6992 
452.3904 
457.1150 
461.8642 
466.6380 
471.4363 
476.2592 
481.1065 
485.9785 
490.8750 
495.7960 
500.7415 
505.7117 
510.7063 
515.7255 
520.7692 
525.8375 



For the circumferences and areas of circles of smaller 
diameters, see Table for Safety- Valves, page. 

To find the circumferences of larger circles, multi- 
ply the diameter by 3.1416. For areas, multiply the 
square of the diameter by .7854. 
12* 



138 CATECHISM OF HIGH PRESSURE, OR 

RULES FOR THE CARE AND MANAGEMENT 
OF THE STEAM-ENGINE. 

First When the engine is stopped at night, the 
drip-cocks should always be left open in order to al- 
low the condensed water to escape from the cylinder. 
They should not be closed for some time after the 
engine is started in the morning. 

Second. Before starting the engine in the morning 
the cylinder should be warmed by admitting some 
steam, and moving the engine back and forth with 
the starting-bar. 

Third. The oil or tallow should never be admitted 
to the cylinder until some time after the engine is 
started and the drip-cocks in the cylinder closed, as 
the tallow w r ould otherwise be carried out by the 
condensed water and lost. 

Fourth. All parts of the steam-pipe and the cylin- 
der should be covered with cloth, felt, or some other 
good non-conductor to prevent radiation and conden- 
sation. 

Fifth. Before packing the piston- and valve-rods 
all the old packing should be carefully removed and 
replaced with new packing, which should be cut in 
suitable lengths, and the joints placed at opposite 
sides of the box. The stuffing-box should then be 
screwed up until the leakage around the rod is stopped, 
and no further, as any unnecessary tightening of 
the stuffing-box will greatly diminish the power of 



NON-CONDENSING STEAM-ENGINES. 139 

the engine and soon destroy the packing by the in- 
creased friction. 

Sixth. Piston-rod packing should always be kept 
in a clean place, as any dust or grit that may become 
attached to it has a tendency to cut or flute the rod. 

Seventh. The spring-packing in the cylinder should 
always be kept up to its proper place, because, if al- 
lowed to become loose, the leakage materially inter- 
feres with the power of the engine. Setting out pack- 
ing-rings requires the exercise of great care, because, 
if set too tightly, the friction produced will not only 
have a tendency to cut the cylinder, but will also 
perceptibly lessen the power of the engine. 

Eighth. The piston should be removed from the 
cylinder at least twice a year, and the joints formed 
by the rings on the flange of the head and the fol- 
lower-plate carefully ground with emery and oil. If 
badly corroded, they should be faced up in a lathe 
and made perfectly steam-tight. 

Ninth. In driving the keys on the cross-head and 
crank-pin, the face of the hammer should never be 
used, unless the end of the key is protected by a piece 
of sheet-brass or copper. 

Tenth. Great care should be taken, when packing 
the spindle of a governor, not to screw the packing 
down too tightly, as that would interfere with the 
free movement of the governor. All the parts of the 
governor should be kept perfectly clean and free from 
the gum formed by the use of inferior qualities of 
lubricating oils. 



HI SUB HI3M OF HIGH FEZ 73 B >S 

fi 7 ~ . Ko more oil should be used on an engine 
than is absolutely necessary, as it is not only a loss, 
but often detracts from the appearance of the engine, 
and greatly yl : Eta free and easy move- 

ment, from the accumulation of gum and dirt on ita 
working par 

Twelfth* In case the crank-pin should heat — - 
which is a common occurrence with engines having 
a narrow bearing on the pin, but more particularly 
with engines that are >ut of line — remove 

the key and slacken the strap and box ; then pour in 
gome flour of sulphur with a liberal supply of oil ; 



Thhieetdh, If the pillow-blocks of an engine 
should heat badly, remove the cap and pour in a good 
supply of pulverized bath-brick and water while the 
engine ion; after d for some time, 

wash out with oil, and wipe the bearing clean with 
waste, and it will be found to give permanent relie£ 

S rteenth. In case any of the bearings of an 
engine should heat through the accumulation of 
matter deposited from the oil used, or sand, grit, or 
whitewash being dropped into the bearings, use a 
strong solution of concentrated lye with oil when 
the engine is in motion. 

_T -etitfk. A steam-engine should shovr 
m rking and general appearance, that all its parts 
are thoroughly cared for. 



yo>-- '.-:■:: exsisg steam- e>~gi>~es. 







: ~-'-~-~i ~-~- 



Manufactured bj Jacob Najlor, a* the People's 

VT;;^ ?„.;, I-,. 



142 CATECHISM OF HIGH PRESSURE, OR 

DIFFERENT KINDS OF ENGINES. 

Q. What is meant by high-pressure or non-con- 
densing engines ? 

A. High-pressure engines are a class of engines in 
which steam is used at a high pressure and exhausted 
into the open air. This class of engines includes 
locomotives and a great variety of stationary engines. 

Q. What is meant by low-pressure or condensing 
engines ? 

A. Low-pressure engines are a class of engines in 
which steam is used at a low pressure and exhausted 
into a condenser, where a vacuum is produced by an 
air-pump; the piston being under the pressure of 
steam from the boiler on one side and the vacuum 
on the other, the difference between the two is the 
effective pressure on the piston. All ocean steamers, 
large river-boat engines, and a great many powerful 
factory engines, belong to this class. 

Q. Is the vacuum perfect in low-pressure engines ? 

A. No ; there is always more or less back pressure, 
caused by wear of the working parts or imperfections 
in the construction of the machinery. 

Q. Are low-pressure engines more economical than 
high-pressure ? 

A. Yes ; low-pressure engines possess great advan- 
tages over high-pressure in point of economy ; but 
the first cost of a low-pressure is nearly double that 
of a high-pressure of the same power. 



NOX-COXDEXSIXG STEAM-EXGIXES. 148 

Q. What is meant by rotative engines ? 

A. Rotative engines are a class of engines in which 
the energy of the steam produces a continuous rota- 
tion of a shaft through the medium of a crank and a 
reciprocating piston. This class of engines includes 
a great variety of designs, namely, horizontal, verti- 
cal, beam, inclined, etc. 

Q. What is meant by rotary engines? 

A. Rotary engines are a class of engines in which 
a continuous rotation of a shaft is caused by the action 
of steam on a piston rotating within a steam-tight 
casing. 

Q. Is the rotary engine as old as the rotative ? 

A. Yes ; one was designed by James Watt, and 
there is hardly a treatise on the steam-engine in exist- 
ence which does not contain an allusion to rotary en- 
gines ; but the writers all agree that nothing would 
be gained by the substitution of the rotary for the 
rotative engine, on account of the great difficulty in 
making the parts steam-tight without producing extra 
friction. 

Q. What is meant by beam-engines ? 

A. Beam-engines are a class of engines in which 
the reciprocating motion of the piston is transmitted 
to the crank through the medium of a beam com- 
monly called a walking-beam. The beam-engine 
was for a long time in great favor with engineers and 
steam users on account of its graceful and nicely- 
balanced movements. But within the past few years 



144 CATECHISM OF HIGH PRESSURE, OR 

beam-engines have been gradually superseded by- 
upright and horizontal engines. 

Q. Does the beam-engine possess any advantage 
over the horizontal engine ? 

A. Yes ; there is less loss of power by friction in 
large beam-engines than in large horizontal engines, 
as the piston hangs plumb in the centre of the cylin- 
der, and has a tendency to assist the downward move- 
ment of the stroke rather than to produce friction, as 
in horizontal engines. The cylinders of beam-engines 
are less liable to wear out of round than those of hori- 
zontal engines. But the first cost of beam-engines is 
more than that of horizontal of the same power. 

Q. Is the beam-engine as old as any of the former ? 

A. Yes ; when steam-engines were first introduced, 
more beam-engines were constructed than any other 
kind. 

Q. What is meant by inclined engines ? 

A. Inclined engines are engines set at an angle or 
an inclined plane for convenience, or to give direct 
motion to some machine or machinery without the 
intervention of belts or gearing. 

Q. What is meant by horizontal engines ? 

A. Horizontal engines are a class of engines in 
which the cylinder, piston, and guides are set hori- 
zontally with the bed-plate. 

Q. What is meant by oscillating engines ? 

A. Oscillating engines are a class of engines in 
which the cylinder swings or vibrates on trunnions, by 



NON-CONDENSING STEAM-ENGINES. 145 

which the motion of the piston is transmitted directly 
to the crank, without the intervention of connecting- 
rod or cross-head. 

Q. What advantage do oscillating engines possess 
over other engines ? 

A. None at all, except in the economy of space. 
The trunnions of oscillating engines soon become 
leaky, and are difficult to repair. The speed of oscil- 
lating engines is very limited. As a factory engine, 
oscillating engines might be said to be a failure. 

Q. What is meant by poppet-valve engines? 

A. Poppet-valve engines are a class of engines used 
almost exclusively in this country. They have four 
valves — two steam and two exhaust — which are 
moved by cams and levers. The poppet-valve engine 
embodies some very good principles, and when in 
good order works very economically. But a limit of 
speed is soon reached in the poppet-valve engine, as 
at a very high speed poppet-valves may not seat 
themselves promptly. Poppet-valve engines take 
their steam very rapidly, and probably have less back 
pressure than slide-valve engines. 

Q. What is meant by slide-valve engines ? 

A. Slide-valve engines are a class of engines in 
which the steam is admitted to the cylinder by means 
of a slide-valve worked by an eccentric or cam. 

Q. Do slide-valve engines possess any advantage 
over other engines in point of economy ? 

A. No; the slide-valve is very imperfect and 
13 K 



146 CATECHISM OF HIGH PRESSURE, OR 

wasteful, as under ordinary circumstances it utilizes 
only about 4 per cent, of the steam-power which 
ought to be produced from the combustion of the 
fuel used, and not more than 10 per cent, under the 
most favorable circumstances. Yet, on account of its 
simplicity of construction, durability, and positive 
movement, and the fact that there is hardly any 
limit to its speed, the slide - valve engine has been 
enabled to compete with the best modern improve- 
ments in steam-engines ? 

Q. What is meant by Corliss engines ? 

A. Corliss engines are a class of high-pressure en- 
gines in very general use. Their design and con- 
struction embody the right principle for the steam- 
engine. They have four valves — two steam and 
two exhaust; they take steam very rapidly, and 
probably have less back pressure on the exhaust than 
any other class of engines in use. They work very 
economically when in good order ; but the great draw- 
back to the Corliss engine is that the valve-gear is 
complicated and expensive, liable to wear very rap- 
idly, and is difficult to repair. 

Q. What is meant by compound engines? 

A. Compound engines are a class of engines which 
embody both the high- and the low-pressure princi- 
ples. Steam is admitted into one cylinder and used 
at high-pressure, and then exhausted into another of 
much larger area and worked on the low-pressure 
principle. Such engines are said to be very econom- 



NON-CONDENSING STEAM-ENGINES. 147 

ical, but they are complicated, and the first cost of 
them is very great. 

Q. What is meant by side-lever engines ? 

A. Side-lever engines are a class of engines (used 
principally for pumping water) in which the motion 
of the piston is transmitted to the pump by side-levers 
or beams. 

Q. What is meant by duplex engines ? 

A. Duplex engines are a class of engines which, 
like the compound, use steam on the high- and low- 
pressure principles, and allow a very great limit of 
expansion. They are principally used for pumping 
water. They work very economically, but, like the 
compound, are complicated and expensive. 

Q. What is meant by Cornish engines ? 

A. Cornish engines are a class of engines in which 
the motion from the piston is communicated to the 
pump by means of a beam. They are used exclu- 
sively for pumping water in cities and mines. Corn- 
ish engines might be said to belong to that class of 
engines called single-acting engines, as the steam acts 
on only one side of the piston. Steam being ad- 
mitted to the cylinder, the piston is forced down to 
the end of the stroke, when the steam escapes to the 
condenser. The opposite movement of the piston is 
accomplished by the inertia or weight on the pump. 

Q. Are Cornish engines more economical than 
other pumping-engines ? 

A. No; the only advantage they possess over 



148 CATECHISM OF HIGH PRESSURE, OR 

other pumping-engines is that they admit of a very 
large measure of expansion in one cylinder. 

Q. What is meant by Bull engines ? 

A. Bull engines are a class of direct-acting pump- 
ing-engines. These engines take their name from 
their inventor — Bull. They do not sustain a high 
reputation either for durability or economy. 

Q. What is meant by trunk engines ? 

A. Trunk engines are a class of engines in which 
the cylinder is stationary, and the reciprocating mo- 
tion of the piston is communicated directly to the 
crank without the intervention of connecting-rod or 
cross-head, through the medium of a trunk or hollow 
tube working through a stuffing-box. Trunk engines 
are very wasteful of steam, as the large mass of metal 
entering into the composition of the trunk, moving, 
as it does, alternately into the atmosphere and steam, 
must cool and condense a great part of the steam. 
The radiation from the interior of the trunk is also 
great. 

Q. What is meant by caloric engines ? 

A. Caloric engines are a class of engines in which 
air is used as a motive power. The air is forced into 
the cylinder by means of an air-pump, and expanded 
by heat, by which means the piston is forced forward 
to the end of the stroke. Caloric engines are inva- 
riably single-acting engines, and their power is very 
limited. 



NON-CONDENSING STEAM-ENGINES. 



149 




KNOCKING IN ENGINES. 

Q. What are the principal causes of knocking in 
engines ? 

A. Knocking in engines generally arises from the 
following causes : 

First Lost motion in the boxes on the cross-head, 
crank-pin, and pillow-blocks, and in the key of the 
piston-rod in the cross-head. 

Q. What is the most effectual remedy for knock- 
ing arising from the above causes ? 

A. Take up lost motion by means of the key, or 
file off the edges of the boxes, if brass-bound. 

Second. Knocking is sometimes caused by the 
crank being ahead of the steam, which in most cases 
can be relieved by moving the eccentric forward in 
order to give more lead on the valve. 

Third. Knocking is caused in many cases by too 
much lead on the valve. The simplest remedy for 
13* 



150 CATECHISM OF HIGH PRESSURE, OR 

this is to move the eccentric back so as to give less 
lead. 

Fourth, Knocking is sometimes caused by the ex- 
haust closing too soon. The best remedy for this 
would be to enlarge the exhaust-chamber in the valve. 

Fifth. Knocking is in some cases produced by 
there not being sufficient clearance between the 
piston and the cylinder-head at the end of the stroke. 
The remedy for this kind of knocking would be to 
turn off the heads of the cylinder on the inside, so as 
to give more clearance. 

Sixth. Knocking sometimes arises from the wrist 
of the cross-head and the crank-pin becoming worn 
out of round. The most effective remedy for this 
cause is to file the crank-pin and wrist perfectly 
round. 

Seventh. Knocking is often induced by the cylinder 
not being counter-bored the necessary depth. In such 
cases the piston-rings wear a shoulder at each end of 
the cylinder, and whenever the keys are driven or 
the packing-rings set out, the edges strike these 
shoulders and cause the engine to knock. The most 
practical remedy for knocking arising from this 
cause is to recounter-bore the cylinder. 

Eighth. Knocking is sometimes caused by the en- 
gine being out of line. The surest remedy for this 
kind of knocking would be to put the engine exactly 
in line. 

Ninth. Knocking often arises from shoulders be- 



N0N- CONDENSING STEAM-ENGINES. 151 

coming worn on the ends of the guides in cases where 
the gibbs on the cross-head do not run over. The 
most reliable remedy for such knocking would be 
to replane the guides. 

Tenth. Knocking is sometimes caused by the fol- 
lower-plate being loose. The best preventive for 
such knocking is to bring the bolts up tight. To do 
so, it is sometimes necessary to remove the deposit of 
rust or grease in the bottom of the holes. 

Eleventh. Knocking is very often caused by the 
packing around the piston-rod being too hard and 
tight. The most effectual remedy for that is to re- 
move all the old packing from the box and replace 
it with new, and only screw the box up sufficiently 
tight to prevent the escape of steam ; for any extra 
friction on the rod is a great loss of power, and has a 
tendency to destroy the packing. 

Twelfth. The knocking heard in the steam-chest is 
sometimes caused by lost motion in the jam-nuts or 
yoke that forms the attachment between the valve 
and rod. The remedy for this would be to remove 
the cover of the steam-chest and readjust the jam- 
nuts on the valve-rod. 

VACUUM. 

Q. What is a vacuum ? 

A. The literal meaning of the term vacuum is 
space unoccupied by matter. 

Q. Suppose the cylinder of a steam-engine be filled 



152 CATECHISM OF HIGH PRESSURE, OR 

with steam that is vaporized from a few drops of 
water, can it be said to be void of matter ? 

A. No ; but condense that steam to its original 
bulk into water, and withdraw this water from the 
cylinder, and the space formerly occupied by the 
steam will be unoccupied ; no matter remaining in 
the cylinder, then there is what is termed a vacuum. 

Q. Suppose this operation to have taken place un- 
der the piston of a steam-engine, would there be any 
resistance to be overcome in the descent of the piston? 

A. No; the pressure of the atmosphere alone, 
which is 15 pounds to the square inch, would suffice 
to force the piston down with a power equal to the 
degree of vacuum formed. 

Q. Were the first steam-engines constructed on this 
principle ? 

A. Yes ; the first steam-engines were constructed 
with the upper end of the cylinder open to the at- 
mosphere ; steam was then admitted below the piston 
to raise it ; and this steam being condensed in the 
cylinder by the application of cold water, the pres- 
sure of the atmosphere alone caused the downward 
stroke of the piston. 

Q. Suppose steam at 5 pounds pressure to the 
square inch above the atmosphere, or, in other 
words, 5 pounds pressure on the steam-gauge, (which 
in reality is 20 pounds to the square inch,) be 
applied to the piston of an engine under the con- 
ditions above stated, what would be the effect ? 



N0X-C0NDEXSIXG STEAM-EXGINES. 153 

A. If the pressure of the atmosphere be 15 pounds 
to the square inch, there will be a pressure of 20 
pounds exerted on the piston ; but if the pressure 
of the atmosphere is only 14 pounds to the square 
inch, as is often the case, the pressure on the piston 
would be only 19 pounds to the square inch. 

Q. How do you explain that ? 

A. Because the resistance of the atmosphere on 
the safety-valve would be less, and the steam in the 
boiler also less in proportion to the reduced pres- 
sure of the atmosphere. 

Q, Does it often happen that low-pressure engines 
heavily loaded vary their speed with the varying 
pressure of the atmosphere ? 

A. Yes. 

Q. Suppose that the vacuum is not perfect, (in 
practice it is never so,) and that there remains in 
the cylinder some uncondensed steam, the resistance 
of which is equal to 3 pounds to the square inch, 
what would be the effect on the engine ? 

A. Then the steam on the upper side of the piston, 
at 5 pounds to the square inch, above the pressure 
of the atmosphere, would act with an effective force 
of only 17 pounds to the square inch because the 
upper side of the piston having exerted upon it a 
pressure equal to a pressure of 20 pounds to the 
square inch and the under side of the piston had a 
resistance of 3 pounds to the square inch, the effec- 
tive pressure would be only 17 pounds. 



154 CATECHISM OF HIGH PRESSURE, OR 

Q. Is a vacuum power ? 

A. No ; all power in the steam-engine is derived 
from the pressure of the steam on the piston ; if 
there is no resistance on one side of the piston, the 
whole pressure on the other side is available. When- 
ever there is resistance on one side of the piston, 
whatever the amount may be, it must be deducted 
from the pressure on the other side. 

THE INDICATOR. 

The instrument known by the name of the Steam- 
Engine Indicator was invented by the celebrated 
James Watt, For a considerable period Watt kept 
the knowledge of that useful instrument to himself, but 
being obliged at last to send an engine abroad, and 
being responsible for its erection and proper work- 
ing, he furnished a mechanic, whom he sent out to 
superintend the erection of the engine, with an Indi- 
cator, having previously instructed him in the use 
of the instrument. 

Since the days of Watt, the Indicator has received 
several important improvements. 

Q. What is the advantage of the Indicator? 

A. The Indicator enables us to calculate with ac- 
curacy the pressure of steam exerted on the piston 
through the whole length of the stroke ; it also shows 
at what part of the cylinder the piston is, and when 
the valves open or close. 



NON-CONDENSING STEAM ENGINES. 155 

Q. Is it possible to tell these things without the 
use of the Indicator ? 

A. No, uot with any degree of accuracy. At a 
glance the Indicator reveals the inner working of the 
steam-engine, and by the use of the instrument, the 
good and bad qualities of the engine are registered 
on paper by the engine itself. 

Q. Do you know of any other advantage to be 
gained by the use of the Indicator? 

A. Yes ; by means of the Indicator the ow T ner of a 
factory may ascertain the whole power he is using, 
also the force required to overcome the friction of 
his engine and machinery, or the power required for 
any single room, or any particular machine, or any 
number of machines. 

Q. Is there any other important knowledge we can 
obtain, concerning the steam-engine, by the use of 
the Indicator? 

A. Yes ; by means of the Indicator we are enabled 
to calculate how much more power an engine .will 
exert by an increase of pressure, or by different de- 
grees of expansion, according to the circumstances 
of the case. 

Q. Would an extended knowledge of the use of 
the Indicator be of great importance to engineers 
and owners of steam-engines? 

A. Yes ; by a skilful use of the Indicator they 
could obtain a knowledge of the condition of every 
description of engines ; also how to increase the power 



158 CATECHISM OF HIGH PRESSURE, OR 

tion of the Indicator ; for he declared that the Indi- 
cator was to the proprietor of a steam-engine what 
the mariner's compass is to the captain of a ship 
navigating the sea. 

Q. Will you explain how to apply the Indicator 
to steam-engines ? 

A. Yes ; but in order to do so it will be first ne- 
cessary to give a description of the instrument itself. 

First The tap, S, forms a communication between 
the cylinder of the Indicator and the cylinder of the 
engine. There is a small hole in the side of the tap 
which opens into the tap-plug, and when the tap is 
open to the cylinder of the steam-engine and the In- 
dicator, this small hole is closed by the plug being 
turned with its perfect side against the hole. When 
the tap is closed, the connection with the engine- 
cylinder is cut off. The small hole in the tap is then 
open through the plug to the cylinder of the Indica- 
tor, so that any steam remaining between the piston 
of the Indicator and the plug of the tap may escape 
into the atmosphere, and allow the pencil attached to 
the piston of the Indicator to settle down to the at- 
mospheric line. 

Second. The cylinder of the Indicator is fitted with 
a piston, the rod of which is shown at E. This piston 
is accurately ground into the cylinder, thereby avoid- 
ing packing ; and when properly oiled and cleaned, 
it is steam-tight, except at very high pressures, where 
perfect tightness is not required, as any small por- 



NON-CONDENSING STEAM-ENGINES. 159 

tion of steam which may escape cannot affect the 
bulk of the pressure in the cylinder. From this con- 
struction the piston works freely with little friction. 

Third. The piston-rod, R, is attached to the spiral 
spring, S, within the tube or casing, F, placed above 
the steam-cylinder of the instrument. This spring is 
so adjusted that when the piston-index is forced one- 
tenth of an inch above the atmospheric line, 0, 
marked on the scale, E, it represents 1 pound pres- 
sure of steam. The pointer forced upward each tenth 
of an inch, up to 25 tenths, will represent as many 
pounds pressure to the square inch. In the same 
way, when the vacuum is formed in the engine-cylin- 
der, the spring will be distended by the pressure of 
the atmosphere upon the upper side of the Indicator- 
piston, and the piston will be forced downward as*many 
tenths of an inch as the degree of rarity, or the quan- 
tity of steam extracted from the engine-cylinder in 
pounds per square inch below the pressure of the 
common atmosphere. 

Fourth. Affixed to the casing there is the scale, E, 
with the atmospheric line, 0, in the centre. The 
tenths below to lo indicate the vacuum, and 
above to 25 tenths, the steam pressure above the 
atmospheric pressure. 

Fifth. The pencil-holder, G, is attached to the pis- 
ton-rod, Pi, through an aperture cut in the casing, 
F, to allow the pencil-holder to move up and down 
with the piston-rod of the Indicator. The pencil can 



160 CATECHISM OF HIGH PRESSURE, OR 

be screwed backward or forward, to obtain the exact 
length required, and is adjusted by a spring to allow 
it to accommodate itself to any little inequalities there 
may be on the revolving cylinder or the paper. In 
all cases a soft and good pencil should be used. The 
less the pressure upon the paper, the less the resist- 
ance to the free action of the piston. 

Sixth. I is the revolving cylinder outside the 
casing, F. This cylinder revolves on its own axis. 
The paper on which the diagram is to be taken is 
fixed around this cylinder, and held in its place by 
the clip, J. On the bottom of the cylinder there is a 
cord round the pulley, K, which, after passing over 
the swivel-pulley, a, is then attached to the cross- 
head of the engine. It will be obvious that the trav- 
erse of the cross-head will pull the cylinder as far 
round as the string thus travels. On the relaxation 
of the string, caused by the return movement of the 
engine-piston, the pulley will again take up the cord, 
because an internal spring, similar to the spring 
of a self-winding measuring-tape, is enclosed in the 
revolving cylinder. The traverse of the cross-head 
pulls the cylinder one w r ay round and the spring the 
other. By means of the cord attached to the cross- 
head of the engine, there is thus produced a regular 
traversing motion of the cylinder, J; and as the pen- 
cil presses at the same time against the paper afhxed 
to the cylinder, and also moves up and down with 
the Indicator-piston — which piston is propelled by 



NON-CONDENSING STEAM-ENGINES. 161 

the same force as the engine-piston — the piston will 
describe a diagram according to the circumstances. 

Seventh. The area of the cylinder of the Indicator 
is a quarter of a square inch, and each tenth of an 
inch on the index represents 1 pound pressure to the 
square inch of the piston of the engine. The spring, 
£, compressed, shows the steam pressure. Distended, 
it shows the atmospheric pressure upon the piston of 
the Indicator caused by the formation of the vacuum 
in the engine-cylinder, varying in accordance with 
the pressure of the uncondensed steam left in the 
cylinder. This spring is so adjusted as to meet the 
requirements of the pressure as it increases. When 
the steam exceeds 25 pounds to the square inch 
above the pressure of the atmosphere, there is an ad- 
ditional spring enclosed in a case for higher pres- 
sures, up to 90 pounds to the square inch, or for a 
still further increased pressure, if required, which 
is to be screwed on to the top of the casing, F. This 
additional spring is represented at M. The piston- 
rod of the Indicator passes up the centre of the 
spring, M, when it is fixed on the top of the casing, 
F, and comes in contact with the top attached to the 
second spring ; so that instead of the resistance of 
only one there is the resistance of two springs for 
high-pressure steam. 

Eighth On the scale, E, for high pressure, the 
distances are marked thirty to the inch for steam 
above 25 pounds — one-thirtieth of an inch represent- 
14* ^ 



162 CATECHISM OF HIGH PRESSURE, OR 

ing 1 pound pressure to the square inch on the steam 
side. The scale on the vacuum side, ten to the inch, 
or one-tenth of an inch, represents, 1 pound pressure 
to the square inch whether with high- or low-pressure 
steam. It should be borne in mind that whatever 
may be the pressure of the steam, high or low, when 
the engine is a non-condensing or high-jn-essure en- 
gine, the vacuum side of the Indicator is not required. 

As to the Application. — The Indicator should be 
connected with the cylinder of the steam-engine by 
means of holes drilled and tapped into the clearance 
at each end of the cylinder, on the side opposite to 
the steam-ports ; nipples should be screwed into these 
holes and elbows attached to their outer ends, in order 
to form a connection by means of a T, into which the 
Indicator should be screwed as near the centre of the 
cylinder as convenient, so that the pressure commu- 
nicated from the steam-cylinder to the Indicator may 
be as uniform as possible. 

The following diagram (No. 1) is taken from one 
of Wright's Cut-off High-pressure Steam-engines. It 
will be seen that it is very perfect. Attention is also 
called to the fulness of the expansion lines, E, above 
the theoretical curves, T; this it is claimed is due to 
the temperature of the steam in the cylinder being 
kept up beyond the point of cut-off by a steam-jacket. 
It is also claimed that the steam pressure in the 
cylinder from the commencement of the stroke to the 
cut-off point, L t is equal to the full boiler pressure. 



JNUoN-UUJN SENSING STEAM-ENGINES. 163 

DIAGRAM. No. 1. 




S L. Steam line. T C. Theoretical curve. E L. Expansion line. 

DIAGRAM. No. 2. 




S L. Steam line. T C. Theoretical curve. 1, 2, 3, etc. Divisions of the 
Diagram. 



164 CATECHISM OF HIGH PRESSURE, OR 

A perfect Diagram. — According to Mariotte's law, 
the expansion-curve (No. 2, p. 163) should be a 
hyperbolic curve, where there are no extraneous cir- 
cumstances to cause it to be otherwise ; but unfortu- 
nately, in practice, this perfection is not attainable. 
Were Mariotte's law literally true — owing to the time 
required for the steam to enter and leave the cylin- 
der, clearance of piston, leakage of valves and piston, 
and condensation in cylinder — it would be impossible 
to show a perfect diagram having all the corners 
well denned and the expansion line a true hyperbolic 
curve. 

EXPLANATION. 

A diagram with the steam-corner rounded shows 
the valve to have little or no lead, the steam being 
admitted upon the piston easily. 

A diagram square and pointed shows the valve to 
have too much lead ; that it opens too quickly, ad- 
mitting the steam upon the piston with too great a 
force before the crank is in a position to receive it. 
This will in most cases cause the engine to tremble, 
and also the Indicator. 

A diagram too much rounded at the commence- 
ment of the exhaust-corner shows want of lead, or a 
quicker opening of the valve on the exhaust side. 
In many instances the steam passages are too small ; 
in such cases the exhaust ought to be open sooner 
than if the passages w r ere of good proportion. 



NON-CONDENSING STEAM-ENGINES. 165 

KEMAEKS. 

It must be understood that every change in the 
engine which diminishes the area of the diagram by 
the rounding of its corners, diminishes the power of 
every stroke; for the space enclosed in the pencil-line 
exactly represents the power of a stroke of the engine, 
with the exception of the rounding of the lead corner. 

While the expansion diminishes the power of each 
stroke, the reduced power of the engine is more than 
compensated for by the saving in the steam con- 
sumed. 

RULE FOR COMPUTING THE POWER OF A, 
DIAGRAM. 

To compute the power of the diagram, set down 
the length of the spaces formed by the vertical lines 
from the base, in measurements of a scale accompa- 
nying the Indicator, and on which a tenth of an inch 
usually represents a pound of pressure ; add up the 
total length of all the spaces, and divide by the num- 
ber of spaces, which will give the mean length, or 
the mean pressure upon the piston in pounds per 
square inch; multiply the area of the piston in 
square inches by the pressure in pounds per square 
inch, and by the speed of the piston in feet per min- 
ute, and divide by 33,000, which gives the actual 
number of horse-power. 



166 CATECHISM OF HIGH PRESSURE, ETC. 

THE GOVERNOR. 

In devices for regulating the speed of steam-en- 
gines we find that the principle of centrifugal force 
has received the most attention, and has been practi- 
cally applied oftener than any other since the days 
of Watt, who first applied a Governor to the steam- 
engine. 

The main object to be attained by the Governor is 
uniform speed of the engine under severe changes of 
machinery and varying steam pressure. A great 
amount of mechanical skill and capital have been 
expended, within the past few years, in efforts to im- 
prove the Governor, and the ingenuity of engineers 
and machinists has been taxed to make it sensitive 
without impairing its steadiness ; and, as a result, 
there have been several Governors brought to notice, 
each of which is claimed to be a decided improve- 
ment on the Governor as first applied. The Govern- 
ors constructed by Corliss, Porter, Judson, Shives, 
Jenkins, Conde, Pickering, and Brown are extensively 
used, and their merits are doubtless familiar to most 
engineers and steam users in this country. 

CONDE'S AMERICAN GOVERNOR. 

The cut on the opposite page represents Conde's 
American Safety-stop Governor. The novelties of 
this Governor consist in an improved double-acting 
valve, by which the Safety-stop is effected, and the 



1G8 



CATECHISM OF HIGH PRESSURE, OR 



sensitive action given to the Governor. The compen- 
sating-wheel changes and regulates the speed of the 
engine as required, and the increased motion-move- 
ment regulates the velocity of the balls as they ap- 
proach an outward plane. The valve, as shown in 



My. 2 




Fig. No. 2, consists of a series of rings (connected by 
internal ribs) forming three or more ports, through 
which the steam passes from similar ports formed in 
the chamber by a second series of rings connected by 
ribs within the globe. By thus constructing the valve 
with three or more ports, greater sensitiveness is 



KOX-COXDENSIXG STEAM-EXGINES. 169 

gained ; for in the downward movement of the valve 
three ports are cutting off steam instead of one, thus 
requiring only one-third the variation to do the same 
work, and but one-third the necessary change of en- 
gine speed to act on the Governor. The Safety-stop 
takes effect by the valve moving upward ; the ports 
in the valve passing the ports in the chamber when 
the balls drop through any accident, from the belt 
breaking or otherwise, instantly closing all communi- 
cation with the engine. This form of Safety-stop 
cannot fail to act so long as the Governor is in working 
order. This stop is simple and reliable, and in no 
way interferes with the free action of the Governor. 
The compensating-wheel, as seen in the large cut, 
allows of a variation of speed in the engine at will. 
It is connected to the main frame of the Governor by 
a sleeve and screw, so that when operated either way, 
the whole upper part of the Governor is raised or 
lowered — changing the position of the valve in its 
seat, and letting in more or less steam, as the case may 
be. It is claimed that this is the only correct arrange- 
ment for changing the speed of an engine. But the 
most noticeable feature of this Governor is, that there 
are no levers, weights or springs to help its operation or 
complicate its parts ; its operation is controlled by 
the simple and reliable principle of centrifugal force. 
15 



170 CATECHISM OF HIGH PRESSURE, ETC. 

SHORT RULES FOR CALCULATING THE SIZE 
OF PULLEYS FOR GOVERNORS. 

To find the diameter of Governor shaft-pulleys : 
Multiply number of revolutions of engine by diam- 
eter of engine shaft-pulley, and divide product by 
number of revolutions of Governor. 

To find diameter of engine shaft-pulley : Multiply 
number of revolutions of Governor by diameter of 
Governor shaft-pulley, and divide product by num- 
ber of revolutions of engine. 

THE INJECTOR. 

Of all the inventions of the mechanic and the 
scientist, nothing approximates so nearly to per- 
petual motion as the instrument now in general use 
and known as the Injector. It is one of the most 
beautiful productions of man's genius for the utiliza- 
tion of scientific purposes. 

The Injector consists of a slender tube, through 
which steam from the boiler passes to another, or in- 
ner tube, concentric with the first. The latter tube 
conducts a current of water from a pipe into the 
body of the Injector. Opposite the mouth of this 
second tube, and detached from it, is a third fixed 
tube, open at the end facing the water supply-pipe, 
and leading from the Injector to the boiler. 

The steam and water supply-pipes are fitted with . 






Irj&St. 




172 CATECHISM OF HIGH PRESSURE, OR 

stop-valves, and the feed-pipe to the boiler with a 
check-valve. 

When the instrument is ready for use, by simply 
opening the steam-valve steam enters the small 
steam-pipe and rushes out at its extremity, picking 
up the whole stream of water leaps across the open 
space with a loud hissing noise, and plunges with its 
burden of w^ater into the open end of the feed-pipe 
at a tremendous velocity. Thus it will be seen that 
the steam that was admitted to the Injector from the 
boiler returns to the boiler, carrying with it more than 
twenty times its weight of water — not a drop of 
water is lost, not a particle of steam wasted. 

Q. Can you explain the action of the Injector? 

A. The principle on which the Injector works is 
that which is understood as the "lateral action of 
fluid." It was discovered by Venturi and Nichol- 
son about 70 years ago. It is simply this : steam 
being admitted to the inner tube of the Injector, and 
the central conical valve being withdrawn, the steam 
escapes in a jet near the top of the inlet water-pipe. 
If the level of the water be below the Injector, the 
escaping jet of steam, by its superficial action (or 
friction) upon the air around it, forms a partial va- 
cuum in the inlet-pipe. The water then rises in vir- 
tue of the external pressure of the atmosphere. Once 
risen to the jet, the water is acted upon by the steam 
in the same manner as the air had been seized and 
acted upon in first forming the partial vacuum into 
which the water rose. 



NOX-CONDEXSIXG STEAM-ENGINES. 173 

Q. How can you account for the great surplus 
energy displayed in the working of the Injector, by 
which steam is taken from one boiler, at a pressure 
of, say 60 pounds to the square inch, and enabled to 
force water into another boiler under a pressure of 
100 pounds to the square inch, or even more. 

A. In this way : the velocity with which steam flows 
into the atmosphere is about 1500 feet per second ; 
now let us suppose that steam is issuing with the 
full velocity due to the pressure in the boiler through 
a pipe an inch in area ; the steam is condensed into 
water at the nozzle of the Injector without suffering 
any change in its velocity. From this cause its bulk 
will be reduced, say 1000 times, and, therefore, its 
area of cross-section — the velocity being constant — 
will experience a similar reduction. It will then be 
able to enter the boiler again by an orifice T oV o tn P art 
of that by which it escaped. Now it will be seen 
that the total force expended by the steam through 
the pipe, on the area of an inch, in expelling the 
steam-jet was concentrated upon the area T oVo tn °f 
an inch, and therefore was greatly superior to the op- 
posing pressure exerted upon the diminished area. 
15* 



174 



CATECHISM OF HIGH PRESSURE, OR 



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NON-CONDENSING STEAM-ENGINES. 175 

Q. Why is it that the temperature of the feed- 
water decreases as the steam pressure increases ? 

A, As the temperature of the steam increases with 
the pressure above a certain temperature of feed- 
water, it would be impossible to condense the steam 
in the Injector, and, as a consequence, the instrument 
would fail to work. 

Q. Is the Injector more or less economical than 
the pump ? 

A. In point of economy, perhaps the advantage 
would be slightly in favor of the pump ; but the ad- 
vantages, if any, would be very trifling, which will 
be evident when we remember that with the Injector, 
as with the pump, waste heat may be employed to act 
upon the water between the feeding apparatus and the 
boiler, the difference being simply this : that with the 
pump the water will pass into the heating apparatus 
at its natural temperature, and will get all the heat it 
acquires before entering the boiler from the waste 
steam, while in the case of the Injector the water in 
passing through the instrument will acquire a certain 
amount of increase in temperature at the expense of 
the steam from the boiler before it comes in contact 
with the waste heat. This fraction, then, of the sup- 
ply which might otherwise be derived from the ex- 
haust steam, is all that is lost by the Injector. But 
it might be said, in favor of the Injector, that it re- 
quires no belt, packing, nor even repairs, and it oc- 
cupies but very little space. 



176 CATECHISM OF HIGH PRESSURE, OR 

DOUBLE-ACTING BUCKET-PLUNGER STEAM- 
PUMP. 

The opposite cut represents an extremely simple 
and compact vertical steam -pump, provided with 
crank and fly-wheel. The pump is of the combined 
piston and plunger variety, and has but two valves ; 
though possessing the same advantages as respects a 
steady delivery as the ordinary double-acting pump. 
It is intended for pumping all kinds, of fluids. 
It is a double-acting piston-pump, the piston having 
a trunk on top. It has but one receiving and one 
discharge valve. The water is received only on the 
upward stroke, the amount being equal to the full 
capacity of the cylinder. Only one-half, however, is 
discharged, owing to the smaller area of the upper 
side of the piston. On the downward stroke, the 
water in the cylinder is forced out by the piston — one- 
half being discharged, the other half flowing into 
the upper end of the cylinder. These pumps are 
very superior as a fire-pump, for the reason that they 
will always start off at once when the steam is let on, 
which is very essential in a pump for this duty ; as 
the time lost, in case of fire, to get an unreliable 
pump at work, is many times of more loss than the 
entire cost of a good pump. 

They are made of any size to discharge from 5 
to 5000 gallons per minute, and with either metal 
or rubber valves. 



SON-CONDENSIXG 



STEAM-ENGINES. 



177 



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178 CATECHISM OF HIGH PRESSURE, OR 

THE HEALD AND SISCO PATENT CENTRIFUGAL 
PUMPS— VERTICAL AND HORIZONTAL, 



Many devices have been employed for raising 
water and other liquids. Among the oldest and 
most general are those which depend, either wholly 
or in part, on atmospheric pressure. Of these are 
the pumps containing valves, and a tight piston 
moving in a straight cylinder. The numerous de- 
fects of this kind of pump long ago led the inventive 
mind to seek a more efficient substitute— a pump 
which, with a continuous flow, would raise more 
rapidly with less power, and would be more durable. 
The problem also required that anything capable of 
flowing should be raised as though it were clear 
water. Mud, sand, bark, etc., must prove no obstacle. 

It was obvious, from the first, that the perfect 
pump must work without valves. The objections to 
valves are so manifest as to need no mention here. 
But without valves the pump could not have a 



\ 

NON-CONDENSING STEAM-ENGINES. 179 

light piston. In short, the ideas of direct pressure 
and of atmospheric aid must be discarded, and a 
radically different system discovered, if possible. 

Reflections of this sort, we should say, finally led 
to the building of pumps on the principle of the 
" Fan Bellows." This principle consists essentially 
in the rapid revolution of fans or arms in a scroll, 
sweeping or whirling the contained air to whatever 
vent might be found ; the centrifugal momentum ac- 
quired in the revolution reacting from the inner 
walls of the scroll, and resolving itself into a force 
acting in the direction of the discharge. 

In making a pump on this plan, no new principle 
was involved. But there was great merit in the 
novel application of the old idea. A long stride was 
made towards the solution of the problem when the 
first Centrifugal Pump was placed in the water. 

The new pump was deservedly received with gen- 
eral favor. There were, however, certain defects still 
to be remedied - — the principal one being a manifest 
waste of power and loss of efficiency, owing to the 
interference of the arms of the wheel with theii* own 
work. Reflection on this point led to the invention 
of the Hollow Arm Piston by Mr. Heald. This 
beautiful device was patented in 1865, and is already 
famous as one of the finest inventions of the age. 
The pump, of which it is the distinguishing feature, 
has taken first premiums at New Orleans (1871), 
Cincinnati and Brooklyn (1872), and also at the 



180 



CATECHISM OF HIGH PRESSURE, OR 



Fair of the American Institute of the same year, 
after severe and protracted tests by the judges ap- 
pointed for the purpose. 

There are several thousands of these pumps in use 
by tanners, paper-makers, contractors, and wreckers, 
all over the United States, the Canadas, and Europe. 

NOISELESS BOILER FEED-PUMP. 




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DIRECTIONS FOR SETTING UP STEAM-PUMPS. 

Never use smaller pipes than the connections on 
the pump call for, and where long or crooked pipes 
are used, they should be larger. Use check-valve 
and strainer on the suction-pipe. 



NON-CONDENSING STEAM-ENGINES. 181 

Run discharge-pipe of full size to the boiler, with 
check-valve between pump and boiler. 

By reducing the diameter of a pipe i, it diminishes 
its capacity to h. 

A pipe 2 inches diameter, 100 feet long, will de- 
liver but i the quantity a pipe 2 inches diameter and 
2 inches long, with same pressure. 

Avoid angles, turns and bends in pipe where it is 
possible, as they retard the flow much more than is 
generally imagined. Where they must be used, 
make the turn on as large a circle as convenient. 

If very hot water is to be pumped, the supply must 
be above the pump, so that the water will flow into it ; 
as it is impracticable to raise it by suction. 

Water expands by heating ; therefore a pump large 
enough to furnish a given quantity of cold water 
would not be large enough if the water is heated. 

Run the exhaust-pipe down from the pump where 
it is possible, that the condensed steam may flow off 
through it. 

Care should be taken to guard against leaks in the 
suction-pipe, as a very small leak destroys the effective- 
ness of a pump. 

Q. What should be the capacity of a pump or 
Injector to feed any particular steam-boiler ? 

A. As a cubic foot of water per hour is taken as 

a standard for a horse-power, the pump or Injector 

should be able to discharge more than a cubic foot 

of water per hour for each horse-power for which the 

16 



182 CATECHISM OF HIGH PRESSURE, OR 

boiler is rated ; for instance, for a 10 horse-power 
boiler, the pump or Injector ought to be able to dis- 
charge 15 cubic feet of water per hour; for a 20 
horse, 25 cubic feet of water, and so on in proportion. 

A TABLE, 

Containing the Diameters, Circumferences, and Areas of Cir- 
cles, and the contents of each in gallons, at 1 foot in depth. 

UTILITY OF THE TABLE. 

EXAMPLES. 

1. Required the circumference of a circle, the di- 
ameter being jive inches. 

In the column of circumferences, opposite the given 
diameter, stands 15.708 inches, the circumference 
required. 

2. Required the capacity, in gallons, of a cylinder, 
the diameter being 4 feet and depth 10 feet. 

In the fourth column from the given diameter 
stands 93.9754, being the contents of a cylinder 4 feet 
in diameter and 1 foot in depth, which being multi- 
plied by 10 gives the required contents, 9391 gallons. 

3. Any of the areas in feet multiplied by .03704, 
the product equals the number of cubic yards at 1 
foot in depth. 

4. The area of a circle in inches multiplied by the 
length or thickness in inches, and by .263, the pro- 
duct equals the weight in pounds of cast iron. 



NON-CONDENSING STEAM-ENGINES. 



183 



Diam. 


Circ. In. 


Area. In. 


Gallons. 


Diam. 


Circ. In. 


Area. In. 


Gallons. 


1 in. 


3.1416 


.7854 


.04084 


6?in. 


19.635 


30.679 


1.59531 


i 


3.5343 


.9940 


.05169 


1 


20.027 


31.919 


1.65979 


i 


3.9270 


1.2271 


.06380 


£ 


20.420 


33.183 


1.72552 


1 


4.3197 


1.4848 


.07717 


1 


20.813 


34.471 


1.79249 


* 


4.7124 


1.7671 


.09188 


1 


21.205 


35.784 


1.86077 


i 


5.1051 


2.0739 


.10784 


ft 


21.598 


37.122 


1.93034 


1 


5.4978 


2.4052 


.12506 


7 in. 


21.991 


38.484 


2.00117 


i 


5.8905 


2.7611 


.14357 


h 


22.383 


39.871 


2.07329 


2 in. 


6.2832 


3.1416 


.16333 


& 


22.776 


41.202 


2.14666 


I 


6.6759 


3.5465 


.18439 


f 


23.169 


42.718 


2.22134 


i 


7.0086 


3.9760 


.20675 


i 


23.562 


44.178 


2.29726 


t 


7.4613 


4.4302 


.23036 


t 


23.954 


45.663 


2.37448 


£ 


7.8540 


4.9087 


.25522 


i 


24.347 


47.173 


2.45299 


1 


8.2467 


5.4119 


.28142 


* 


24.740 


49.707 


2.53276 


i 


8.6394 


5.9395 


.30883 


8 in. 


25.132 


50.265 


2.61378 


I 


9.0321 


6.4918 


.33753 


h 


25.515 


51.848 


2.69609 


3 in. 


9.4248 


7.0686 


.36754 


i 


25.918 


53.456 


2.77971 


£ 


9.8175 


7.6699 


.39879 


§ 


26.310 


55.088 


2.86458 


* 


10.210 


8.2957 


.43134 


i 


26.703 


56.745 


2.95074 


1 


10.602 


8.9462 


.46519 


i- 


27.096 


58.426 


3.03815 


1 


10.995 


9.6211 


.50029 


i 


27.489 


60.132 


3.12686 


t 


11.388 


10.320 


.53664 


ft 


27.881 


61.862 


3.21682 


1 


11.781 


11.044 


.57429 


9 in. 


28.274 


63.617 


3.30808 


£ 


12.173 


11.793 


.61324 


h 


28.667 


65.396 


3.40059 


4 in. 


12.566 


12.566 


.65343 


4 


29.059 


67.200 


3.49440 


ft 


12.959 


13.364 


.69493 


I 


29.452 


69.029 


3.58951 


i 


13.351 


14.186 


.73767 


h 


29.845 


70.882 


3.68586 


§ 


13.744 


15.033 


.78172 


ft 


30.237 


72.759 


3.78347 


i 


14.137 


15.904 


.82701 


1 


30.630 


74.662 


3.88242 


i 


14.529 


16.800 


.87360 


i 


31.023 


76.588 


3.98258 


4 


14.922 


17.720 


.92143 


10in. 


31.416 


78.540 


4.08408 


1 


15.315 


18.665 


.97058 


k 


31.808 


80.515 


4.18678 


5 in. 


15.708 


19.635 


1.02102 


i 


32.201 


82.516 


4.29083 


1 


16.100 


20.629 


1.07271 


t 


32.594 


84.540 


4.39608 


JL 
4 


16.493 


21.647 


1.12564 


ft 


32.986 


86.590 


4.50268 


& 


16.886 


22.690 


1.17988 


i 


33.379 


88.664 


4.61052 


* 


17.278 


23.758 


1.23542 


i 


33.772 


90.762 


4.71962 


ft 


17.671 


24.850 


1.29220 


1 


34.164 


92.885 


4.82846 


i 


18.064 


25.967 


1.35028 


llin. 


34.557 


95.033 


4.94172 


i 


18.457 


27.108 


1.40962 


ft. 


34.950 


97.205 


5.05466 


6 in. 


18.849 


28.274 


1.57025 


I 


35.343 


99.402 


5.16890 


I 


19.242 


29.464 


1.53213 


§ 


35.735 


101.623 


5.28439 



184 



CATECHISM OF HIGH PRESSURE, OR, 



Diam. 


Circ. In. 


Area. In. 


Gallons. 


Diam. 


Circle. 


Area. 


Gallons. 


lliin 


36.128 


103.869 


5.40119 


Ft. 


in. 


Ft. 


in. 


Feet. 


1 ft. depth. 


f 


36.521 


106.139 


5.51223 


2 


5 


7 


7 


4.5869 


34.3027 


1 


36.913 


108.434 


5.63857 


2 


6 


7 


101 


4.9087 


36.7092 


2 


37.306 


110.753 


5.75916 


2 


7 


8 


H 


5.2413 


39.1964 










2 


8 


8 


4i 


5.5850 


41.7668 


Ft. in. 


Ft. in. 


In feet. 


1 ft. depth. 


2 


9 


8 


71 


5.9395 


44.4179 


1 


3 n 


.7854 


5.8735 


2 


10 


8 101 


6.3049 


47.1505 


1 1 


3 4f 


.9217 


6.8928 


2 


11 


9 


U 


6.6813 


49.9654 


1 2 


3 8 


1.0690 


7.9944 














1 3 


3 11 


1.2271 


9.1766 


3 




9 


5 


7.0686 


52.8618 


1 4 


4 21 


1.3962 


10.4413 


3 


1 


9 


Si 


7.4666 


55.8382 


1 5 


4 5| 


1.5761 


11.7866 


3 


2 


9 111 


7.8757 


58.8976 


1 6 


4 8£ 


1.7671 


13.2150 


3 


3 


10 


2* 


8.2957 


62.0386 


1 7 


4 111 


1.9689 


14.7241 


3 


4 


10 


51 


8.7265 


65.2602 


1 8 


5 2| 


2.1816 


16.3148 


3 


5 


10 


81 


9.1683 


68.5193 


1 9 


5 51 


2.4052 


17.9870 


3 


6 


10 in 


9.6211 


73.1504 


1 10 


5 9 


2.6398 


19.7414 


3 


7 


11 


3 


10.0846 


75.4166 


1 11 


6 2| 


2.8852 


21.4830 


3 


8 


11 


61 


10.5591 


78.9652 










3 


9 


11 


9i 


11.0446 


82.5959 


2 


6 31 


3.1416 


23.4940 


3 


10 


12 


5£ 


11.5409 


86.3074 


2 1 


6 6i 


3.4087 


25.4916 


3 l: 


12 


31 


12.0481 


90.1004 


2 2 


6 91 


3.6869 


27.5720 














2 3 


7 01 


3.9760 


29.7340 


4 




12 


61 


12.5664 


93.9754 


2 4 


7 31 


4.2760 


32.6976 















PISTON-ROD PACKING. 

It is probable that on the whole, with steam-en- 
gines of plain construction, no part is more fre- 
quently out of order, and gives greater annoyance, 
than piston-rod packing. Hemp, when properly 
used, serves a good purpose, but its usefulness is 
limited, particularly where steam of a high pressure 
is used, as it soon loses its elasticity and, in conse- 
quence, becomes worthless. A vast deal of study 
and ingenuity have been applied to the removal of 



NON-CONDENSING STEAM-ENGINES. 185 

this annoyance and the production of a durable pis- 
ton-rod packing. Wire-gauze, gum, soap-stone, jute, 
asbestos, and a great variety of other materials, have 
been tried, and with only partial success. 

There has always been a general want of a perma- 
nent and reliable piston-rod packing. 

Rule for finding the size of packing for piston or 
valve-rods : 

Measure the piston or valve-rod; then measure stem 
of stuffing-box ; divide the difference between them 
by two. 

For example : rod 2 inches, box 4, packing 1 inch. 
Rod 1 inch, box 2, packing J inch. Rod f inch, box 
1J, packing I. Rod 2 inches, box 3 J, packing |. Rod 
1J inches, box 4 inches, packing li. 

INCRUSTATION. 

All waters contain more or less mineral matter, 
which is acquired by percolation through the earth's 
surface, and consists principally of carbonate of lime 
and magnesia, sulphate of lime and chloride of 
sodium in solution, clay, sand, and vegetable matter 
in suspension. 

Some waters contain far less mineral ingredients 
than others, such as rain-water, the water of lakes 
and large rivers, whilst wells, springs, and creeks 
hold large quantities in solution. 

When such water is boiled, the carbonic acid is 
16* 



186 CATECHISM OF HIGH PRESSURE, OR 

driven off, and the carbonates, deprived of their sol- 
vents, are rapidly precipitated in a finely crystallized 
form, tenaciously adhering to the surface of the iron. 
Chloride of sodium, and all such soluble salts, are 
precipitated in the same way by supersaturation. 
This combined deposit, of which carbonate of lime 
forms the greater part, remains adherent to the inner 
surface of the boiler, undisturbed by the force of the 
most violent boiling currents. Gradually this accu- 
mulation becomes harder and thicker, until it is as 
dense as porcelain, thereby preventing the proper 
heating of the water by any fire that can ]je placed 
in the furnace. The high temperature necessary to 
heat water through thick scale will sometimes con- 
vert the scale into a substance resembling glass. 

The evil effect of scale in steam-boilers is due to 
the fact that it is a non-conductor of heat. The con- 
ducting power of scale compared with that of iron is 
as 1 to 37 ; consequently, a greater amount of fuel is 
required to heat water in an incrusted boiler than 
if the same boiler were clean. 

Scale jg of an inch thick will require an expendi- 
ture of fifteen per cent, more fuel. This expenditure 
increases as the scale becomes thicker ; thus, when it 
is a quarter of an inch thick, sixty per cent, more 
fuel is needed to raise water in a boiler to any given 
heat. If the boiler is badly scaled, the fire surface 
of the boiler must be heated to a temperature ac- 
cording to the thickness of the scale. 



NOX-CONDENSING STEAM-ENGINES. 187 

For example : To raise steam to a pressure of 90 
pounds, the water must be heated to a temperature 
of 324° Fah. If a quarter of an inch of scale inter- 
venes between the shell and the water, it would be 
necessary to heat the fire surface of the boiler nearly 
600°, or 100° Fah. above the maximum strength of 
iron. Now, it is a well-known fact, that the higher the 
temperature at which iron is kept, the more rapidly 
it oxidizes, and is made liable at any time to bulge 
or crack by internal pressure, and is often the cause 
of explosions. 

Within the past few years a great many patent 
remedies for the removal and prevention of scale have 
been offered to the owners of steam-boilers, but, after 
a fair test of all these remedies, they have been nearly 
all abandoned, as not only useless, but even in many 
cases injurious, attacking and corroding the clean 
and sound iron, and producing no visible effect on 
the scale other than to change the color, and convey 
the impression that it was removed. 

At a recent meeting of the American Eailway 
Mechanics' Association, held at Louisville, Ky., the 
committee to whom was referred the subject of boiler 
incrustations, reported that they had prepared and 
issued, through the secretary of the association, a cir- 
cular of questions to all the master mechanics of 
various railroads throughout the country, in order 
to elicit such information as they might possess on 
this subject. In compliance therewith, communica- 



188 CATECHISM OF HIGH PRESSURE, OR 

tions had been received from forty master mechanics ; 
and although the number is small compared with the 
whole number of roads, yet it is nearly double that 
of any previous year, and the information so obtained 
is correspondingly extensive and valuable, confirm- 
ing in substance the theory advanced in a paper read 
in convention last year, to the effect that the only 
effectual w T ay to prevent incrustation is to purify the 
water, if possible, before it is allowed to enter the 
boiler. To this end the committee directed its efforts, 
and had given special attention to the reports of those 
who have experimented, with a view thereby of as- 
certaining the best and cheapest mode of accomplish- 
ing the same. 

From all communications received, it is found that 
most of the roads located in the Eastern and Southern 
States are troubled but little with incrustation, w T hile 
those in the Middle States are variously affected — 
some suffering greatly, others none at all. Western 
roads suffer most, many of them finding it necessary, 
in order to maintain average economy in fuel and rea- 
sonable safety to the boiler, to take out flues once in 
six to twelve months, for the purpose of removing 
scale from both boiler and tubes. Railway engi- 
neers in Western States realize similar difficulties in 
a greater or less degree, according to location. Mr. 
De Clerq, of the Toledo, Peoria, and Warsaw Rail- 
road, reports having used batteries, and also many 
different kinds of powders, for the removal of incrus- 



NON-CONDENSING STEAM-ENGINES. 189 

tations, but all without any decided results. He 
finds distilled water the best of anything he has ever 
used to prevent lime incrustation. He thinks soft 
water, w r ell filtered, will keep a boiler free from mud 
and scale. 

Mr. Ham, of the New York Central, stated that he 
can run with economy, on the Eastern Division, four 
years without taking out the flues ; while on the Mid- 
dle Division, on account of lime and scale, he has to 
take them out, on an average, every year and a half, 
and on the Western Division every two years. He 
finds it necessary, on the Middle Division, to put new 
sheets in the bottom of the cylinder part of boiler on 
an average every five years ; and, with good water, 
has only repaired that portion of the boiler once in 
eight to ten years. He has used batteries and pow- 
ders, but finally abandoned them all. He is troubled 
with deposit of scale on the crown-sheet ; gives crown- 
bars one inch clearance, and considers it as good as 
more space. He knows nothing equal to pure soft 
water to keep boilers free from mud and scale. 

The following extract was taken from a report of 
a committee of the Railway Master Mechanics' Asso- 
ciation, held in Boston in the summer of 1872. 
After a series of exhaustive experiments, the com- 
mittee reported that the only preventive against 
incrustation was the use of pure water in steam- 
boilers. It w T as also stated that the introduction into 
the boilers of any of the so-called remedies now in 



190 CATECHISM OF HIGH PRESSURE, OR 

use — whether they be batteries, powders, antilami- 
nas, or filters — was comparatively useless for the re- 
moval or prevention of scale. 

It w r as also stated that the extra expense in one 
year, from impure water and incrustation, would 
amount to $75,000 for every hundred locomotives. 
The committee considered that to boil sufficient water 
to supply a locomotive for one year, running 31,000 
miles, would require an extra expenditure of $236 
for fuel ; but they considered that that was the only 
reliable means for preventing incrustation and all 
manner of ruptures and leaks in boilers. 

Q. What is the most effective method for the pre- 
vention of incrustation ? 

A. The most effective method to prevent incrusta- 
tion in boilers would be to boil the water in a tank, 
and then allow it to settle before using in the boiler. 
By this means the carbonates and minerals w T ould 
become separated and deposited on the bottom of the 
tank, and the pure water could then be drawn off. 
Another effective method would be to blow out the 
boiler every evening, before the minerals that were 
held in suspension, by the agitation of the water, 
could settle and become attached to the sheets, A 
third j^ould be to use rain-water, if possible. Any 
of the above three remedies would effectually prevent 
incrustation in steam-boilers, although it might be 
said that the two former are hardly practicable. 

Q. What is the most effectual mechanical means 
that you know of for removing scale from boilers ? 



N0X-C0XDEXSIXG STEAM-ENGINES. 191 

A. By picks and scrapers. 

Q. Are boilers sometimes injured by this mode of 
cleaning ? 

A. Yes ; the sheets of the boilers are sometimes 
cut by the use of the pick in the hands of ignorant 
or careless persons. 

Q. Is this method practicable in all boilers ? 

A. No ; only in cylinder boilers, as it is utterly 
impossible to remove scale from flue, tubular, or loco- 
motive boilers by any mechanical means. 

Q. What is the best preventive against scale be- 
coming hard and firmly attached to the surface of 
the flues or tubes ? 

A. Never to let the surface of the flues or tubes 
become dry after the boiler is blown out. The boiler 
should always be again filled before the scale be- 
comes dry. 

Q. Mention some of the most common remedies 
resorted to for the purpose of preventing scale in 
boilers. 

A. Indian meal, potatoes, oil-cake, molasses, gum 
caoutchouc, slippery elm, white-oak blocks, refuse 
logwood, and a variety of other vegetable substances, 
were at times tried without much success. 

Q. What is the effect of vegetable substances on 
boilers ? 

A. They are sometimes as equally destructive to 
boilers as scale or incrustation. 

Q. How do you explain that ? 



192 CATECHISM OF HIGH PRESSURE, OR 

A. All vegetable matter contains more or less 
acid, and the iron is more open to attack from the 
acid than the scale is; so that some boilers suffer 
fearfully from the corrosion of the acid in the vege- 
table substances. 

Q. What is the composition of most of the differ- 
ent patent boiler powders now presented to steam 
users for the prevention of scale ? 

A. Eefuse logwood, sal soda, and yellow ochre. 

Q. What is the effect of the above-named articles ? 

A. They have a tendency to deposit on the parts 
of the boiler most exposed to the fire ; uniting the 
loose scales in solid masses, and causing the boiler to 
leak — very often to bulge or crack. 

Q. Do you think it possible to separate the min- 
erals from feed-water in the heater, by raising the 
w T ater to a very high temperature, and forcing it 
through straw, shavings, or similar substances ? 

A. No ; the capacity of any heater is so limited, 
and the time so short, that it is unreasonable to ex- 
pect that any quantity of matter could be deposited. 
Even if a separation should take place in the heater, 
the matter will be carried into the boiler and be de- 
posited on the iron. 

Q. Is there any difference in scales formed under 
different pressures and different temperatures ? 

A. Yes ; scales formed under low pressures and 
low temperatures are nearly always soft and porous ; 
while scales formed under high pressures and high 
temperatures are hard and glassy. 



NON- CONDENSING STEAM-ENGINES. 193 

Q. Would the removal of scale or incrustation be 
attended with economical results ? 

A. Yes ; it would effect a saving of thousands of 
tons of coal annually, and a preservation of hundreds 
of lives destroyed by explosions that might be attri- 
buted to this cause alone. 

Q. Do you think that pure water is the only effec- 
tive means to prevent the accumulation of scale in 
steam-boilers ? 

A. Yes ; for while several hundred patents encum- 
ber the records of the patent-offices of the "United 
States and England, not one of them answers the 
purpose for which it was patented. 

BOILER EXPLOSIONS. 

The risk of life and property involved in the use 
of the steam-boiler is still, as it has always been, a 
source of constant anxiety to the engineer and to the 
public. 

Explosions continually take place, with the most 
disastrous results. Occurring without warning, and 
occupying but an instant of time, it is generally diffi- 
cult, if not impossible, except in rare instances, to as- 
certain with certainty their true cause, as there is 
seldom a unanimous opinion on the part of experts 
who examine into the causes after the event. 

But experience in the care and management of 
steam-boilers leaves no doubt in the minds of intelli- 
17 N 



194 CATECHISM OF HIGH PRESSURE, OR 

gent men but that the principal causes that operate 
to produce explosions are — inequality of expansion 
caused by some parts of the boiler becoming heated 
to a higher temperature than others; allowing the 
water to become dangerously low and pumping in 
cold water ; sediment or incrustation being deposited 
on the parts of the boiler most exposed to the action 
of the fire, preventing the water from coming in con- 
tact with the iron, thereby allowing the plates to be- 
come overheated or burned ; faulty construction ; 
leakage, causing oxidation or rusting away of the 
iron; internal grooving; over - pressure ; excessive 
firing ; ignorance, recklessness, and mismanagement. 
The above causes include everything that experience 
and intelligence teach us to believe would cause a 
steam-boiler to explode ; and it will be seen that the 
remedy for every one of these is within easy reach of 
the mechanic and the owner of steam-boilers. It 
might be said, without fear of contradiction, that the 
number of boilers that explode every year from all 
other causes are very few compared with those that 
occur from over-pressure and excessive firing. 

It is also a well-known fact that a great many 
destructive steamboat and locomotive explosions have 
occurred just as the engine w T as starting, after standing 
still for some time. These, like all others, were the 
result of ignorance or carelessness. When an engine 
is stopped, and the communication between the cylin- 
der and the boilers is closed, the whole heat of the 



XOX-CONDENSING STEAM-EXGINES. 195 

fire acts on the plates of the boiler directly over and 
around the fire ; the circulation ceases, and the iron 
and water become surcharged with heat to such an 
extent that, when the engine is started and the pres- 
sure on the surface of the w T ater lessened, all the 
water on the surface of the iron directly over the fire 
immediately flashes into steam of tremendous elastic 
force. Whereas, if care had been taken to cover the 
fire with fresh coal, and the feed-pump or Injector 
had been started to force water into the boiler, the 
circulation of the w T ater would have been kept up, 
and the heat that was transmitted to the iron would 
have been absorbed by the fresh coal and the feed- 
water. 

The practical conclusion to be derived from all 
known facts in connection with the generation of 
steam is, that water in a boiler under some circum- 
stances, — such as slow continued evaporation when a 
boiler is at rest, — can be nearly deprived of air, and the 
circulation being then feeble, portions of the water in 
contact with the plates may be heated to a higher 
temperature than that of the mass of water above it; 
under such circumstances, the sudden starting of the 
engine, or any other cause of agitation, producing an 
active circulation of the water, might cause a certain 
increase of the steam in such quantities, and of such 
elastic force, as would in many instances result in 
serious accident. 

But that we shall continue to have frequent and 



196 CATECHISM OF HIGH PRESSURE, OR 

terrible steam-boiler explosions, there is no reason to 
doubt, so long as steam is used as a mere brute force, 
and so long as coroners' juries can be found to exon- 
erate engineers and owners of steam-boilers from any 
blame, though it might be in evidence that the ex- 
plosion, resulting in terrible loss of life, was brought 
about by their recklessness or avarice. The Lord's 
command, "Thou shalt not kill," limiting the 
power of masters over their servants, was one of the 
first steps towards the civilization of the world. But 
this solemn injunction does not seem to have much 
weight w T ith some owners of steam-boilers in our days. 
Perhaps this arises from the fact that it is not in evi- 
dence that Moses was the owner of a steam-boiler. 

Whenever a boiler does explode, which is a fre- 
quent occurrence in different parts of the country, it 
will be noticed that the self-styled experts are always 
on hand to ventilate their pet theories. Many of 
these theories are the merest vagaries, and only go 
to show the ignorance of their authors. The public 
read these speculations, and, in the absence of any 
intelligent refutation, swallow them down, and con- 
clude that the whole subject is involved in dark 
mystery. Now, we claim that there is no mystery 
about steam-boiler explosions ; they are all cause and 
effect. The City Inspection and the Hartford In- 
spection and Insurance Company have been demon- 
strating this fact for the past four or five years. Out 
of 3,000 steam-boilers in this city we did not have 
one explosion for over four years. Now, was it be- 



NON-CONDENSING STEAM-ENGINES. 197 

cause engineers and owners of steam-boilers were 
more careful, and carried the water higher in their 
boilers than they had previously done, or was it be- 
cause the City Inspector and the Insurance Company 
discovered defects that would lead to explosions, and 
compelled the owners of the boilers to repair them, 
and use their boilers at a safe working pressure ? 

It would be safe to say that the Hartford Steam- 
Boiler Inspection and Insurance Company have done 
more to prevent steam-boiler explosions in the last 
five years than had been done by all the laws passed 
by the National and State Legislatures for the past 
twenty years. 

Few persons have any idea of the great internal 
strain continually exerted on the shells of boilers ; for 
instance : in a boiler 54 inches in diameter, circum- 
ference 169 inches, pressure 85 pounds — a very com- 
mon pressure to carry on steam-boilers — there would 
be continually exerted upon each inch in length of 
the shell a pressure of 14,365 pounds ; and if the 
boiler is 18 feet, or 216 inches in length, the entire 
pressure on the shell of that boiler is 3,102,840 
pounds or 1,556 tons. 

In a boiler 36 inches diameter, circumference 113 
inches, with a pressure of 70 pounds to the square 
inch, there would be a pressure of 7,910 pounds on 
every inch in length ; and if the boiler was 14 feet 
in length, the whole pressure on the shell would be 
664 tons. 
17* 



198 CATECHISM OF HIGH PRESSURE, OR 

STEAM- AND FIRE-REGULATOR. 

The numerous devices which have been employed 
by engineers for maintaining a uniform pressure of 
steam in boilers, shows the importance of a contriv- 
ance for this purpose. As a consequence, many 
steam- and fire - regulators have been introduced to 
the public, but most of them, from complexity or 
want of good workmanship, have failed to give satis- 
faction, and in many instances have proven them- 
selves to be of more injury than advantage. 

This Improved Regulator is self-adjusting, simple 
and durable in its construction, and not liable to de- 
rangement or loss of sensitiveness from time or use ; 
having perfect control of the clamper, it will, when 
once set to any required pressure, maintain that 
pressure in the boiler, without any attention from the 
engineer or fireman. In fact, 

The following advantages are secured by 
this Regulator : 

First. Uniformity of pressure in the boiler within 
three pounds. 

Second. Economy of fuel averaging ten per cent. 

Third. Freedom from danger of explosion by ex- 
cess of pressure. 

The sizes of the Regulator are, No. 1, No. 2, No. 3, 
No. 4. The No. 2, with one ball at extreme end of 
lever, will close at 60 pounds per square inch ; No. 3, 
in same position, 40 pounds per square inch. For 
higher pressures, extra balls are used. 



NON-CONDENSING STEAM-ENGINES. 



199 




200 CATECHISM OF HIGH PRESSURE, OR 

CENTRAL AND MECHANICAL FORCES. 

Q. What is centrifugal force ? 

A. It is the force with which a revolving body 
tends to fly from the centre. 

Q. What is centripetal force ? 

A. It is the force that draws to the centre, or 
counteracts the centrifugal tendency. 

Q. What is gravity ? 

A. Gravity is a downward pressure or weight. 

Q. What is specific gravity ? 

A. It is the comparative density or weight that 
one body has to another of equal bulk. 

Q. What is the centre of gravity ? 

A. It is that point in a body on which, if rested or 
suspended, the whole will remain in a state of equi- 
librium or rest. 

Q. What is the force of gravity ? 

A. It is an accelerated velocity which heavy bodies 
acquire when falling from a state of rest. 

Q. What is meant by the centre of oscillation? 

A. It is a point in vibrating bodies in which all 
the force is collected. 

Q. What is the centre of gyration ? 

A. It is the point in revolving bodies into which 
the momentum of the mass is concentrated. 

Q. What is motion ? 

A, It is the effect of an impulsive force acting in 
such a manner as to impart linear or circular velo- 
city by motive power. 



NON-CONDENSING STEAM-ENGINES. 201 

Q. What is inertia ? 

A. It is that property of matter by which it tends 
when at rest to remain so, and when in motion to 
continue in motion. 

Q. What is capillary attraction ? 

A. It is the property observable in all porous sub- 
stances of raising water or other fluids above the 
natural level. 

Q. What is friction ? 

A. Friction is the resistance experienced when one 
body is rubbed upon another, and is supposed to be 
the result of natural attraction. 

Q. What are logarithms ? 

A. Artificial numbers which stand for natural 
numbers. 

Q. How are the mechanical powers distinguished ? 

A. In the following order, viz. : lever, pulley, in- 
clined plane, wheel and axle, and screw. 

MENSURATION. 
OF THE CIRCLE, CYLINDER, SPHERE, ETC. 

1. The circle contains a greater area than any 
other plane figure bounded by an equal primeter or 
outline. 

2. The areas of circles are to each other as the 
squares of their diameters. 

3. The diameter of a circle being 1, its circumfer- 
ence equals 3.1416. 



202 CATECHISM OF HIGH PRESSURE, OR 

4. The diameter of a circle is equal to .31831 of its 
circumference. 

5. The square of the diameter of a circle being 1, 
its area equals .7854. 

6. The square root of the area of a circle, multi- 
plied by 1.12837, equals its diameter. 

7. The diameter of a circle multiplied by .8862, or 
the circumference multiplied by .2821, equals the 
side of a square of equal area. 

8. The sum of the squares of half the chord and 
versed sine divided by the versed sine, the quotient 
equals the diameter of corresponding circle. 

9. The chord of the whole arc of a circle taken 
from eight times the chord of half the arc, one-third 
of the remainder equals the length of the arc ; or, 

10. The number of degrees contained in the arc 
of a circle multiplied by the diameter of the circle 
and by .008727, the product equals the length of the 
arc in equal terms of unity. 

11. The length of the arc of a sector of a circle, 
multiplied by its radius, equals twice the area of the 
sector. 

12. The area of the segment of a circle equals the 
area of the sector, minus the area of a triangle whose 
vertex is the centre, and whose base equals the chord 
of the segment ; or, 

13. The area of a segment may be obtained by di- 
viding the height of the segment by the diameter of 
the circle, and multiplying the corresponding tabular 
area by the square of the diameter. 



N0N- CONDENSING STEAM-ENGINES. 203 

14. The sum of the diameter of 2 concentric circles, 
multiplied by their difference and by .7854, equals 
the area of the ring or space contained between them. 

15. The sum of the thickness and internal diame- 
ter of a cylindric ring, multiplied by the square of 
its thickness and by 2.4674, equals its solidity. 

16. The circumference of a cylinder, multiplied 
by its length or height, equals its convex surface. 

17. The area of the end of a cylinder, multiplied 
by its length, equals its solid contents. 

18. The area of the internal diameter of a cylin- 
der, multiplied by its depth, equals its cubical 

.capacity. 

19. The square of the diameter of a cylinder, mul- 
tiplied by its length and divided by any other re- 
quired length, the square root of the quotient equals 
the diameter of the other cylinder of equal contents 
or capacity. 

20. The square of the diameter of a sphere, mul- 
tiplied by 3.1416, equals its convex surface. 

21. The cube of the diameter of a sphere, multi- 
plied by .5236, equals its solid contents. 

22. The height of any spherical segment or zone, 
multiplied by the diameter of the sphere of which it 
is a part, and by 3.1416, equals the area or convex 
surface of the segment ; or, 

23. The height of the segment, multiplied by the 
circumference of the sphere of which it is a part, 
equals the area. 



204 CATECHISM OF HIGH PRESSURE, OR 

24. The solidity of any spherical segment is equal 
to three times the square^ of the radius of its base, 
plus the square of its height, and multiplied by its 
height and by .5236. 

25. The solidity of a spherical zone equals the 
sum of the squares of the radii of its two ends, and 
one-third the square of its height, multiplied by the 
height and by 1.5708. 

26. The capacity of a cylinder 1 foot in diameter 
and 1 foot in length equals 5.875 of a United States 
gallon. 

27. The capacity of a cylinder 1 inch in diameter 
and 1 foot in length equals .0408 of a United States 
gallon. 

28. The capacity of a cylinder 1 inch in diameter 
and 1 inch in length equals .0034 of a United States 
gallon. 

29. The capacity of a sphere 1 foot in diameter 
equals 3.9156 United States gallons. 

30. The capacity of a sphere 1 inch in diameter 
equals .002165 of a United States gallon : hence, 

31. The capacity of any other cylinder in United 
States gallons is obtained by multiplying the square 
of its diameter by its length, or the capacity of any 
other sphere by the cube of its diameter, and by the 
number of United States gallons contained as above 
in the unity of its measurement. 

TO CALCULATE THE SPEED OF PULLEYS. 

Example 1. To find the size of driving - pulley : 



NON-CONDENSING STEAM-ENGINES. 205 

Multiply the diameter of the driven by the number 
of revolutions it should make, and divide the pro- 
duct by the revolutions of the driver. The quotient 
will be the size of the driver. 

Example 2. The diameter and revolutions of 
driver being given, to find the diameter of the driven 
that shall make a given number of revolutions: 
Multiply the diameter of the driver by its number 
of revolutions, and divide the product by the num- 
ber of revolutions of the driven. The quotient will 
be the size of the driven. 

Example 3. To find the number of revolutions 
of the driven pulley : Multiply the diameter of driver 
by its number of revolutions, and divide by diameter 
of driven. The quotient will be the number of revo- 
lutions of the driven. 

BELTING. 

It is a common error among mechanics and own- 
ers of factories to make the face of their pulleys nar- 
row, in order to economize on the first cost of belting ; 
but this false economy seldom decreases the cost of 
the machinery, and only saves a trifle in the first cost 
of belting. The small amount saved is soon lost by 
the stopping of machinery caused by the slipping of 
belts, strain on the shafting, increased friction, re- 
quiring additional driving-power, and rapid destruc- 
tion of the belts themselves. Were pulleys made of 
a proper size and width and face, and then covered 
18 



206 CATECHISM OF HIGH PRESSURE, OR 

with leather, and belts of proper width run with the 
grain side of leather to the pulley, thousands of tons 
of coal might be saved annually, and also an im- 
mense amount of trouble. 

The importance of covering the face of pulleys 
with leather is realized by but few persons having 
charge of machinery ; full 50 per cent, more work 
can be done without the belts slipping, if the face of 
the pulleys are covered with leather. 

LEATHER BELTS. 

Leather belts used with grain side to pulley will 
not only do more work, but last longer than if used 
with flesh side to the pulley ; this is owing to the fact 
that the grain side is more compact and fixed than 
the flesh side, and more of its surface is brought in 
contact with the pulley. The smoother the two sur- 
faces the less air will pass between the belt and the pul- 
leys. The more uneven the surface of the belt and pul- 
ley the more strain necessary to prevent the belt slip- 
ping; for what is lost by want of contact must be 
made up by extra strain on the belt. 

Leather belts, with grain side to pulley, can drive 
34 per cent, more than flesh side. 

A belt 1 inch wide, travelling 800 feet per minute 
over two smooth pulleys, will develop 1 horse-power. 

A belt 1 foot wide, running at a speed of 70 feet 
per minute over smooth pulleys, will be equal to 1 
horse-power. 



NON-CONDENSING STEAM-ENGINES. 207 

A belt 3 inches wide, running at a speed of 280 
feet per minute, will be equal to 1 horse-power. 

A belt 5 inches wide, travelling 762 feet per min- 
ute over pulleys covered with leather, will develop 
5 horse-power. 

A belt 5 inches wide, in good condition, travelling 
over pulleys covered with leather, running at a speed 
of 1525 feet per minute, will transmit 10 horse-power. 

LACING BELTS. 

In lacing belts great care should be taken that the 
ends intended to butt together should be cut per- 
fectly square ; if not, the belt will stretch more on 
one side than the other, wdiich will greatly impair 
its worth. 

HORIZONTAL BELTS. 

The driving half of horizontal belts should be the 
lower half when practical, as, when the belt stretches, 
the upper half will cover more of the pulley's sur- 
face. Long horizontal belts are better than short 
ones, as their weight increases their contact with the 
pulley. 

PERPENDICULAR BELTS. 

Belts running on pulleys perpendicular to each 
other should be kept tightly strained, as their weight 
tends to decrease their contact with the lower pulleys. 



208 CATECHISM OF HIGH PRESSURE, OR 

GREASING BELTS. 

Belts, if dry or husky, should be greased with a 
mixture of neat's-foot oil and tallow, and dried in by 
the heat of the fire or sun. 

RULES. 

Eule for calculating the width of belts required 
for transmitting different numbers of horse-powers : 

Multiply 36,000 by the number of horse-powers; 
divide the product by the number of feet the belt is 
to travel per minute ; now divide the quotient by the 
number of feet, or parts of feet, of belt in contact 
w T ith the smaller pulley ; divide this last quotient by 6, 
and the result is the required width of belt in inches. 

Eule for calculating the number of horse-powers 
a belt will transmit ; its velocity, and the number of 
square inches in contact with the smaller pulley, 
being given : 

Divide the number of square inches in contact 
with the pulley by 2 ; multiply this quotient by the 
velocity of the belt in feet per minute, and divide by 
36,000 ; the quotient is the number of horse-powers 
the belt will transmit. 






NON-CONDENSING STEAM-ENGINES. 209 

ACCIDENTS. 

KULES FOB THE COURSE TO BE FOLLOWED BY THE 
BYSTANDERS, IN CASE OF INJURY BY MACHINERY, 
WHEN SURGICAL ASSISTANCE CANNOT AT ONCE BE 
OBTAINED. 

If there is bleeding, do not try to stop it by bind- 
ing up the wound. The current of the blood to the 
part must be checked. To do this, find the artery 
by its beating ; lay a firm and even compress or pad 




Fig. 1. Fig. 2. Fig. 3. 

(made of cloth or rags rolled up, or a round stone or 
a piece of wood well wrapped) over the artery, (see 
Figure 1 ;) tie a handkerchief around the limb and 
compress ; put a bit of stick through the handkerchief 
and twist the latter up till it is just tight enough to 
stop the bleeding ; then put one end of the stick under 
the handkerchief to prevent untwisting, as in Fig. 3. 
The artery in the thigh runs along the inner side 
of the muscle in front, near the bone. A little above 
the knee it passes to the back of the bone. In inju- 
juries at or above the knee, apply the compress Jiigh 
18* 



210 CATECHISM OF HIGH PRESSURE, OR 

up on the inner side of the thigh, at the point where 
the two thumbs meet at C in Figure 4, with the knot 
on the outer side of the thigh. When the leg is in- 
ured below the knee, apply the compress at the back 
of the thigh just above the knee at C in Figure 2, 
and the knot in front, as in Figures 1 and 3. 





Fig. 4, Fig. 5- 

The artery in the arm runs down the inner side of 
the large muscle in front, quite close to the bone ; 
lower down it gets farther forward toward the bend of 
the elbow. It is most easily found and compressed 
a little above the middle, (see Figure 5.) 

Care should be taken to examine the limb from 
time to time, and to lessen the compression if it be- 
comes very cold or purple ; tighten up the handker- 
chief again if the bleeding begins afresh. 

A BRIEF HISTORY OP THE STEAM-ENGINE. 

Hero of Alexandria, who flourished about 200 
B. C, has left us a description of a steam-engine by 
which machinery could be set in motion. 

In the year 450 A. D., Anthemius, an architect, 



NON-CONDENSING STEAM-ENGINES. 211 

tried some experiments with steam, which is the 
second attempt on record to use steam as a motive- 
power. 

In the year 1543, Blasgo de Garay, a Spaniard, 
propelled a vessel of 200 tons, in the harbor of Bar- 
celona, by the force of steam. 

In the year 1615, De Caius, a Frenchman, devised 
a machine by which water could be raised in tubes 
through the agency of steam. 

In the year 1630, Branca, an Italian physician, 
ground his drugs by means of a wheel set in motion 
by steam. 

In 1656, the Marquis of Worcester made some 
very important improvements in the steam-engine. 

In the year 1685, some experiments were made 
with steam by Pepin, a Frenchman, who devised the 
mode of giving a piston an up and down movement 
by alternately generating and condensing the steam 
in a cylinder. 

In the year 1698, Savery, an Englishman, con- 
structed a steam-engine superior to any before in- 
vented. 

In the year 1705, Newcomen made some very 
important improvements in the steam-engine. To 
Newcomen belongs the honor of building the first 
engine that bore any resemblance to modern steam- 
engines. 

In the year 1764, James Watt constructed the first 
perfect stationary steam-engine that was ever made 
up to that date. 



212 CATECHISM OF HIGH PRESSURE, OR 

In the year 1769, Nicholas Cugnot constructed the 
first self-moving locomotive-engine. 

In the year 1786, the Marquis Jouffry constructed 
a small steamboat on the Saone. 

In the year 1789, William Symington made a 
voyage in a small steamboat on the Firth of Clyde. 

In the year 1782, Ramsey propelled a boat by 
steam in New York harbor. 

In the year 1788, John Fitch, of Philadelphia, 
navigated a boat by steam on the Delaware River. 

In the year 1793, Robert Fulton made some im- 
portant experiments with steam. 

In the year 1794, Oliver Evans, a native of Phila- 
delphia, constructed the first locomotive or road- 
steamer in America. 

In the year 1803, John C. Stevens, of New York, 
obtained a patent for a steamboat. 

HISTORY OF THE DIFFERENT PARTS OF THE 
STEAM-ENGINE IN DETAIL. 

The inventor of the slide-valve is unknown : it 
was spoken of by Hero 2,000 years ago. 

The valve was made self-acting by a boy named 
Humphrey Potter. 

The eccentric was invented by Murdock, as was 
also the crank. 

The beam and connecting-rod were invented by 
Newcomen. 

The radius and parallel bars were invented by 
Watt. 



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